The history, culture, economy, and population of Yemen have all been influenced by the country's strategic location at the southern entrance of the Red Sea—a crossroads of both ancient and modern trade and communications routes. In the ancient world, the states that occupied the area known today as Yemen controlled the supply of such important commodities as frankincense and myrrh and dominated the trade in many other valuable items, such as the spices and aromatics of Asia. Because of its fertility as well as its commercial prosperity, Yemen was the location of a number of ancient kingdoms; for that same reason, it was known to the ancient Romans as Arabia Felix (Latin: “Fortunate Arabia”) to distinguish it from the vast forbidding reaches of Arabia Deserta (“Desert Arabia”). Later, Yemen was the place where coffee (Arabic: qahwah) was first cultivated commercially, and, before the introduction of coffee plants to other parts of the world, it was long the sole source of that precious bean.

The present Republic of Yemen came into being in May 1990, when the Yemen Arab Republic (North Yemen) merged with the People's Democratic Republic of Yemen (South Yemen). By stipulation of the unification agreement, Sanaa, formerly the capital of North Yemen, functions as the political capital of the country, while Aden, formerly the capital of South Yemen, functions as the economic centre. The two components of Yemen underwent strikingly different histories: whereas North Yemen never experienced any period of colonial administration at the hands of a European power, South Yemen was a part of the British Empire from 1839 to 1967. The contemporary borders are largely a product of the foreign policy goals and actions of Britain (United Kingdom), the Ottoman Empire, and Saudi Arabia.

The coastal plain ranges in width from 5 miles (8 km) to as much as 40 miles (65 km). Low mountains rising from 1,000 to 3,500 feet (300 to 1,100 metres) lie between the low hills of the plain and the great central massif, which has many peaks in excess of 10,000 feet (3,000 metres); the highest is Mount Al-Nabī Shuʿayb, which rises to 12,336 feet (3,760 metres). Toward the east-northeast, the mountains subside rather rapidly into the eastern highlands (2,500–3,500 feet 【750–1,100 metres】), which drop off to the sandy hills of the Rubʿ al-Khali.

Yemen is an arid country, and there are no permanent watercourses. The regular rainfall that occurs in some areas drains, in the northern part, westward toward the Red Sea through five major watercourses (wadis) and, in the southern part, southward into the Gulf of Aden and the Arabian Sea through three major watercourses. The largest of the latter is the Wadi Ḥaḍramawt (Hadhramaut Valley), which has been renowned since antiquity for its frankincense trees and which historically has been the locus of a number of sophisticated city-states. Together with their tributaries and lesser neighbours, these intermittently flowing channels slice the highlands and central massif into a large number of plateaus and ridges. In many places there is evidence of volcanic activity from as recently as a few hundred years ago; the existence of hot springs and fumaroles (volcanic vents) attests to continued subterranean activity. Moreover, the country sits astride one of the most active fault lines in the Red Sea region (Great Rift Basin) and has experienced several severe earthquakes in modern times, including one that shook the Dhamar area in December 1982, killing about 3,000 people and largely destroying several villages and hundreds of smaller settlements.

Soils throughout the country vary from sandy to loamy, and most are low in organic matter, thus limiting agricultural options. In some areas, however, elaborate agricultural terraces cover the mountains from base to peak. The high agricultural productivity of this system is largely attributable to the soil that has been collected and enriched with compost over a period of centuries. In the modern period, neglect and civil conflict have taken their toll on the earthworks, which are particularly vulnerable to erosion. Still, the terraces are largely intact and are a breathtaking feature of mountainous Yemen.

Most of Yemen lies in the border zone between two main weather patterns: the regular northerly winds (from the Mediterranean basin) and the southwest monsoon winds. These create a fairly well-defined seasonal rhythm; the northerly winds predominate during the winter, while in the summer the southwest monsoon brings the primary rains. Cut off from this pattern by the central mountains, the southern fringe areas on the Gulf of Aden experience a markedly tropical climate. In Aden as well as in the north at Al-Ḥudaydah, temperatures often exceed 100 °F (38 °C), with high humidity, whereas in Sanaa (at more than 7,200 feet 【2,200 metres】) the daytime temperature averages just under 70 °F (21 °C), and humidity is low. The higher northern elevations of the central massif experience occasional frosts and dustings of snow during the winter months.

On the Tihāmah, as well as along the southern coastal belt, the average annual precipitation is less than about 5 inches (130 mm); many years record no measurable precipitation. Rainfall increases with elevation; the lower highlands receive about 15 to 20 inches (400 to 500 mm) per year, while the middle highlands around Taʿizz and Ibb average more than 30 inches (750 mm) annually. Different annual cycles characterize the northern and southern parts of Yemen: whereas the north usually has two rainy seasons (March–May and July–September), the south often receives no precipitation except sparse amounts in the summer months. Throughout Yemen, precipitation is erratic and variable from year to year, and lengthy droughts are not unknown; there have been periods as long as five years when precipitation was one-tenth the normal amount. A serious drought occurred during North Yemen's civil war of 1962–70 and had lasting social and economic consequences.

The people of Yemen overwhelmingly consider themselves Arabs (Arab), but they have tended to divide themselves between northern and southern groups, a historical division that has linguistic roots but which is otherwise difficult to trace. Yemenis of northern origin, for example, are said to have descended from Mesopotamians who entered the region in the 1st millennium BC, and they claim ancestry of the biblical figure Ismāʿīl (Ishmael). The southern group, which represents the old South Arabian stock, claims descent from Qaḥṭān, the biblical Joktan.

Ethnic minorities include the Mahra, a people whose roots are unclear and who occupy a part of eastern Yemen, as well as the island of Socotra, and who speak a variant of the ancient Himyaritic language. (See Mahra Sultanate.) On the Tihāmah coastal plain, in-migrations from Ethiopia and Somalia have occurred over many centuries. There is a clear African admixture in the coastal population as well as a distinct social group known as the Akhdām, who perform menial tasks and are the closest thing to a caste in Yemen. In the far north there are still small remnants of the once-large Jewish communities (most migrated to Israel after 1948), while in the area of Aden and the eastern regions there are distinct Somali, Indonesian, and Indian elements in the population, legacies of the British colonial era as well of economic and political ties extending back over two millennia.

Among Arab groups, tribal affiliation (tribe) is another deep-seated component of social identity. Some confederations of tribes have histories spanning more than two millennia. These affiliations continue to serve as a key basis for political and social organization throughout the country, although the postindependence governments of both South Yemen and, to a lesser extent, North Yemen set out to eradicate what then were considered reactionary cultural institutions. Although efforts toward detribalization were at least in part effective, subsequent events indicated that such identifications were still socially, economically, and politically relevant.

More than nine-tenths of Yemenis speak some dialect of Arabic (Arabic language) as their first language, and Modern Standard Arabic—the literary and cultural language of the broader Arab world—is taught in schools. There are several main dialects, but minor differences often occur within smaller geographic areas. The Arabic of the rural areas of the south is still heavily influenced by the ancient South Arabian languages. A dialect of Judeo-Arabic spoken by the Jewish community has fallen almost entirely out of use in Yemen. Hindi, Somali, and several African languages are spoken in pockets. Several ancient Semitic (Semitic languages) dialects, including Bathari, Mehri, and Socotri (Soqotri), remain in a chiefly oral capacity. Those languages have tended to recede as literacy in Arabic has become more common.

Throughout society, the broadest distinctions between population groups are based not on ethnicity but on religious affiliation. Islam (Islām) is the state religion, and the Sunni branch of Islam, represented by the Shāfiʿī (Shāfiʿīyah) school, predominates. The Shīʿite minority comprises the Zaydī (Zaydīyah) school, which has long been politically dominant in the mountainous highlands of the north, and the Ismāʿīlīs, now a relatively small group found in the Haraz region of northern Yemen and in Jabal Manakhah, the mountainous area west of Sanaa. The non-Muslim community is very small, consisting mostly of foreign visitors and workers. All are free to worship as they wish—including the Jewish community—but, as in most conservative Muslim countries, proselytizing of Muslims by non-Muslims is illegal.

Historically, Yemen has had its share of Islamic militants, particularly since the return of combatants who fought in the 1980s on the side of the mujahideen (Arabic: mujāhidūn, “those who engage in jihad”) in the Afghan War (1978–92).

In many respects, the most important contemporary demographic trend has been the emigration of large numbers of males between the ages of 15 and 45 for employment in other countries. The number of such emigrants has fluctuated because of political and economic volatility over the years. Until the last decade of the 20th century, there were more than one million Yemeni nationals employed abroad—chiefly in Saudi Arabia and the smaller Arab countries of the Persian Gulf region, as well as in Great Britain (in the industrial Midlands and in Wales), and in the United States (in industrial areas of the Northeast and Midwest and in the agricultural areas of California). The remittances of these emigrants played an important role in the balance of payments, in radically increasing the income of most Yemenis, and in funding many local development projects. Iraq's invasion of Kuwait in 1990, however, drastically altered the balance of migrant labour. Yemen's neutrality and failure to support a Saudi invitation extended to U.S. forces resulted in Saudi Arabia's retraction of the special status granted to Yemeni workers, forcing as many as one million labourers to return to a newly unified Yemen that was ill-prepared to reabsorb them.

The population of Yemen continues to display characteristics typical of less-developed areas: high birth rate, high infant mortality rate, low levels of literacy, and the ill effects of poor hygiene, unsanitary water supplies, and inadequate public health service. Major health and education programs funded by foreign governments and by the United Nations have attempted to address both structural and programmatic deficiencies.

Despite economic advances since the 1970s—most notably the beginning of the commercial exploitation of oil and natural gas—Yemen is one of the world's poorest and least-developed countries. The majority of Yemenis are subsistence agriculturalists. Only about 3 percent of the country's land is arable (mostly in the west), though roughly one-third is suitable for grazing. During the first half of the 20th century, the rulers in the north (the imams; see Zaydiyyah (Zaydīyah)) achieved and maintained virtual self-sufficiency in food production for their region. By contrast, at the beginning of the 21st century, unified Yemen was heavily dependent on imported food, despite the market expansion and increased investment of the 1970s and '80s. One important reason for this situation was the scarcity and high cost of domestic labour, the result of the exodus of much of the adult male labour force that began in the 1970s. In addition, the remittances of these emigrants (emigration) (most of which were transferred through unofficial channels and therefore not taxed) fueled inflation, driving the prices of domestic food products above those of imported equivalents, such as U.S. grains and Australian meats.

One of the more important issues raised by the merger of the two Yemens was the integration of the socialist command economy of the south and the largely market-driven economy of the north. By the early 1970s the government of the south had nationalized almost all land and housing, along with most banking, industrial, and other business enterprises in the country; thereafter, all new industries and businesses of any size were state-owned and state-operated. Although closer to the opposite pole, industry and business in North Yemen were a hodgepodge of public, public-private, and private enterprises, with most of the bigger and more-important firms being public. The private sector has since been encouraged and has been fueled by remittances from migrant workers.

Yemen's difficult terrain, limited soil, inconsistent water supply, and large number of microclimates have fostered some of the most highly sophisticated methods of water conservation and seed adaptation found anywhere in the world, making possible the cultivation of surprisingly diverse crops. The most common crops are cereals such as millet, corn (maize), wheat, barley, and sorghum; myriad vegetables from a burgeoning truck farm industry have appeared on the market in recent years. There has also been extensive cultivation of fruits—both tropical (mangoes, plantains, bananas, melons, papayas, and citrus) and temperate (pears, peaches, apples, and grapes).

The two main cash crops in the northern highlands are coffee (coffee production) (Coffea arabica) and khat (qāt; Catha edulis). The coffee trade, which began in the 16th century, was originally based on Yemeni coffee, and, for centuries, coffee was the most important and renowned export of Yemen. The port city of Mocha—from which a distinctive style of coffee takes its name—was the point from which most of Yemen's coffee was exported between the 16th and 18th centuries, before more-economical plantation cultivation was introduced in other parts of the world. In Yemen the coffee tree grows best in the middle highlands, at elevations of 4,500 to 6,500 feet (1,400 to 2,000 metres), where khat also flourishes. The latter is an evergreen shrub whose young leaves, which contain an alkaloid, are chewed as a mild stimulant. The production and consumption of khat occupy a prominent position in the culture and economy of Yemen. Increased affluence has allowed a growing section of the population to indulge in its use, which the government has attempted—with little success—to discourage. Greater demand has fueled a substantial increase in khat acreage. Although older coffee terraces are often converted to khat as their productivity declines, much of the land being devoted to khat was formerly considered marginal for commercial agricultural purposes and now benefits from regular soil-enhancement programs and terrace-maintenance efforts.

Beginning in the 1970s, the cultivation of cotton—both in the Tihāmah coastal plain in the north and in the coastal plain east of Aden—was strongly supported by the respective national governments, and for a while it contributed significantly to national income. At the end of the 20th century, a significant decline in world cotton prices, as well as the high costs of initiation and development, meant that the Yemeni cotton industry was not competitive.

The typical Yemeni farmer raises at least some livestock, typically the regional varieties of goats, sheep, or cattle. Agricultural development programs sponsored by Western countries introduced new varieties of dairy and beef cattle in the more temperate regions of the north; aid from foreign governments and international development programs, in the form of technical and monetary assistance, also contributed to livestock-focused projects in Yemen in the 20th century.

Another important economic development has been the growth of both the artisanal and the industrial fishing (commercial fishing) industries. The waters of the Red Sea and the Gulf of Aden are extraordinarily rich in a wide variety of commercially desirable fish and crustaceans. In the past, very small quantities of some species were marketed locally; the foreign technical and financial assistance provided to the fishing industry (notably by the Soviet Union (Union of Soviet Socialist Republics)) contributed markedly to its increased role in the national economy. At the beginning of the 21st century, the developing fishery sector, also increasingly supported by domestic government programs and assistance, was one of the top contributors to Yemen's economy.

The export of oil generates a major portion of national income and government revenues. Oil (petroleum) and natural gas were first discovered in commercial quantity in North Yemen on the edge of the eastern desert near Maʾrib in 1984 by the Hunt Oil Company. Two years later, oil was found by a state corporation of the Soviet Union in the south, near the juncture of the two Yemens and Saudi Arabia. Since then, several other significant finds have been made, most notably the major commercial strike in 1991 in Masīlah, north of Al-Mukallā, by Canadian Occidental (later known as Nexen Inc.); the Masīlah field is one of Yemen's most productive. New exploration and the development of existing finds by several foreign companies continued in the early 21st century. Pipelines in Yemen carry crude oil to export facilities on the Red Sea, the Gulf of Aden, and the Arabian Sea.

As important, if not more so, are Yemen's large proven reserves of natural gas, located mostly in the western part of the country. Yemen has signed agreements with foreign companies to begin full exploitation of natural gas, but in the early 21st century the sector remained underdeveloped, and production was limited. Electricity is mostly generated by oil-burning thermal plants. At the end of the 20th and the beginning of the 21st century, energy restructuring plans provided for the construction of a number of gas-powered plants, with hopes that switching from oil to natural gas as Yemen's principal fuel for meeting electric and other domestic needs would maximize oil available for export and relieve domestic Yemeni oil dependence. Installed electrical capacity does not meet national demands, and scheduled blackouts are common. In the 2000s only about two-fifths of the country was tied into the national grid.

There has never been a thorough survey of Yemen to determine precisely what other mineral resources might be commercially exploitable. Salt is extracted from underground mines near Al-Ṣalīf in the Tihāmah and from surface deposits near Aden in the south. In the past, coal and iron deposits supported a small-scale steel industry (primarily for the manufacture of swords and daggers, particularly the janbiyyah, a symbolic, largely ornamental dagger worn by many Yemeni men). There are deposits of copper, as well as some evidence of sulfur, lead, zinc, nickel, silver, and gold, and surveys in the late 20th and early 21st centuries indicated that some of these deposits were commercially exploitable.

Continuing today in Yemen are traditional handicraft industries that achieved great renown in the past for the quality of their products: jewelry, especially silver and gold filigree; leatherwork; carpets; glass; utensils, especially for cooking; daggers and other metalwork; decorative woodwork; and stained-glass windows. Modern manufacturing enterprises did not contribute to the national income until the 1970s, with the exceptions of the oil refinery in Little Aden (the peninsula that encloses the western side of Aden's harbour), built originally by British Petroleum (BP PLC) in the 1950s and nationalized in 1977, and the cotton textile industry established in North Yemen in the last years of the imamate at the beginning of the 1960s.

The multiyear development plans of the governments of both Yemens after the 1960s focused on the establishment of a more diversified and modern industrial base. Most of these manufacturers were designed as import-substitution enterprises, producing such items as cement, aluminum ware, plastic products, paints, textiles, furniture, cooking oil, foodstuffs, soft drinks, and tobacco products; some have since become significant contributors to the national income. Much of new manufacturing in recent decades has been related to transportation and communications infrastructure: road building, the construction of electrical power stations, electrification and the stringing of telephone lines. The oil and natural gas industry entails—in addition to the foreign primary firms—an array of local subcontractors and allied services. Pipeline construction and maintenance, as well as new refineries, make substantial contributions to the economy.

The Central Bank of Yemen was formed in 1990 from the merger of the central banks of the two Yemens. It is responsible for issuing the rial, the national currency, and for managing the government's foreign exchange and other financial operations. The Yemen Bank for Reconstruction and Development (1962) provides commercial and customer services. Banking is a small sector of the economy; services have traditionally been difficult to obtain since, because of a weak court system, collecting money owed has been difficult. Many Yemenis rely on informal systems to meet financial needs.

For many centuries, trade was the major source of wealth for the states that occupied the southern corner of the Arabian Peninsula. Trade diminished in the 16th century, when the Portuguese set out to control seaborne commerce with the East, turning the Red Sea region, and especially Yemen, into an economic backwater. The only world commodity left to Yemen was the coffee trade, a monopoly that continued for several centuries. The construction of the Suez Canal (completed in 1869) revitalized the Red Sea route between Asia and Europe, proving prescient the British decision to take Aden in 1839. Aden's deepwater berths and sophisticated and extensive port facilities, which the British constructed over the years, made it one of the world's preeminent ports.

Still, trade remained quite modest until the economic boom of the 1970s and '80s; at the height of this boom, the value of Yemeni exports (primarily coffee, cotton goods, and hides and skins) amounted to only a minute fraction of imports, which comprised foodstuffs of all types, manufactured goods (consumer as well as industrial), machinery, transportation equipment, chemicals, and petroleum products—the basic goods demanded by a population formerly isolated from the modern consumer economy. The ratio of exports to imports began to shift dramatically with the start of the export of oil in the late 1980s. With the exception of oil exports, however, Yemen conducts all but an infinitesimal portion of its export trade with its regional neighbours.

Within the service sector, public administration is one of the largest employers. Overall, the service sector employs about one-fourth of the population and accounts for about two-fifths of the gross domestic product (GDP). Tourism accounts for a relatively small portion of the GDP; despite Yemen's rich natural and cultural heritage and government efforts to encourage tourism, the infrastructural underdevelopment and political instability have made many visitors wary of travel to the country.

Although the government acknowledges the right of workers to organize, union membership in Yemen is minimal. All unions are federated within an umbrella labour organization, the General Federation of Trade Unions of Yemen. Collective bargaining is limited, and work stoppages and strikes are permitted only with government approval. More than half of Yemen's workforce is engaged in agricultural labour. Unemployment frequently exceeds 30 percent. Child labour is common, particularly in agriculture, and laws limiting the work hours of children under age 15 are seldom enforced. As is common in Muslim countries, the standard workweek is Saturday through Wednesday.

The country derives most of its income from tax revenue, of which taxes derived from the oil industry are the most significant. There is a personal income tax, and income derived from tariffs and other taxation has traditionally been a major source of the state's non-petroleum-based income. The Islamic tithe (zakāt (zakat)) is administered by the state (though calculated by the individual); the proceeds are intended for the relief of the poor. Before 2000 the undemarcated frontier with Saudi Arabia, as well as the fluid political situation along those portions of the frontier that were demarcated (e.g., near Najrān, Saud.Ar.), made smuggling—and thus the loss of much-needed import duties—a chronic problem for revenue collectors.

Until the 1960s there were virtually no all-weather roads anywhere in Yemen except in the city of Aden. In the last years of the imamate, the first of these roads (roads and highways) were built in the north as part of foreign-aid packages by China, the United States, and the Soviet Union. These first roads—i.e., the one from Al-Ḥudaydah to Sanaa and the one from Mocha (Al-Mukhā) to Sanaa via Taʿizz—represented major feats of engineering. They cut the transportation time between the cities involved from days to hours and set off an explosion of intrastate traffic and trade. Since then, many of the formerly rudimentary roads in the north and south have been paved, and demands for similar improvements have been raised by numerous small towns and villages. Although all the major towns and cities are now served by all-weather roads, there are thousands of miles of tracks that are passable only by all-terrain vehicles; built at an accelerated rate since the mid-1970s, these tracks have provided an outlet for locally produced goods and easier access to consumer products. The former capital cities of Aden and Sanaa remain the transportation hubs of the south and north, respectively, and travel between most of the lesser towns and cities is not possible except through these centres.

The 1970s and '80s saw the development of a public transportation system based on buses and shared taxis. Beginning in the late 20th century, the distribution of goods has been handled primarily by modern trucks, some of immense size; these trucks are often overloaded, and the accident rate on Yemeni roads is disproportionately high.

Until the early 1960s, about three-fourths of North Yemen's very modest international trade passed through Aden. Following the revolution of 1962, however, the new government redirected trade through the Red Sea port of Al-Ḥudaydah (Ḥudaydah, Al-), which was expanded and modernized with major assistance from the Soviet Union. The ports of Aden and Al-Ḥudaydah now handle nearly all of Yemen's sea traffic. Although Al-Ḥudaydah's port is well-equipped, it has experienced periods of serious congestion. Aden's extensive facilities were underutilized during the socialist period. With unification and the major upgrading of port and manufacturing facilities that began in the late 20th century, Aden—which has good road connections to Taʿizz, Ibb, and beyond—will have the ability to handle most of the country's international trade. Yemen's other ports, most notably Mocha and Al-Mukallā (Mukallā, Al-), used chiefly by small craft and for coastal traffic and, in the case of Mocha, for smuggling, began plans for revival in the late 20th century. While Mocha canceled most of its development plans after Yemen's unification, in the early 21st century Al-Mukallā was included in a development program designed to expand the infrastructure of three of Yemen's port cities.

Prior to unification, the state-owned airlines of the two Yemens provided each country with its chief transport link to the outside world for passengers, mail, and light freight. Both airlines, but especially the one in the south, greatly facilitated internal travel and transport between the cities and major towns of Yemen. The two airlines were finally merged nearly a decade after unification. Today, Yemenia (Yemen Airways) operates regular service to a large number of countries in the Red Sea region and to most other Arab states, as well as to a growing number of European transportation hubs. Major airports are at Aden, Sanaa, and Al-Ḥudaydah. There are a number of other smaller airports and airfields located in other cities.

There are relatively few main phone lines in Yemen, and, like many other less-developed countries, Yemen is experiencing a boom in cellular and wireless phone service, with such service being provided by several private companies. The number of televisions and radios per capita is quite high. Television and radio stations are located in the larger cities, and more-affluent Yemenis have access to satellite feeds from other Arab countries and elsewhere. Internet service is sparse, and few people own computers.

The former states of North Yemen and South Yemen had sharply contrasting political systems. North Yemen was a republic governed nominally under a constitution adopted in 1970, suspended in 1974, and largely restored between 1978 and the late 1980s. Although a succession of bodies carried out some of the functions of a legislature, they exercised little real power until the late 1980s. During that period, policy making remained in the hands of a relatively progressive military elite that worked closely with a variety of civilians that included a large and growing group of technocrats, the major tribal leaders, and other traditional conservative notables. Although political parties were formally banned, several parties did exist and operated with varying degrees of influence during and between elections.

South Yemen, also republican in form, had an avowedly Marxist regime, and the political system and economy reflected many of the goals and organizational structures of its “scientific socialism.” The Yemen Socialist Party (YSP), the only legal political organization, determined government policy and exercised control over the state administrative system, the legislature, and the military.

The unified political system created in 1990 represented a pronounced departure from either of the previous ones, in theory and, to a large extent, in practice. The most important change was the decision to establish a multiparty representative democracy.

The 1990 constitution (amended in 1994 and 2001) called for those rights and institutions usually associated with a liberal parliamentary democracy. The head of state is the president, who appoints the vice president and the prime minister; the latter is the head of government. The president holds office for no more than two seven-year terms and is assisted by a cabinet. The bicameral legislature consists of two houses: the House of Representatives, whose members are elected by universal adult suffrage every six years, and the Shūrā (Consultative) Council, whose members are appointed by the president. The legislature oversees the executive, discusses and drafts legislation, and authorizes government budgets and economic plans. The constitution may be modified with a two-thirds vote by the House of Representatives.

The issue of redefining territorial and administrative subdivisions after union was complex. In the north the provinces had corresponded to more or less obvious topographical regions. Each province was subdivided into qaḍāʾ (district) and nāḥiyah (tract) levels, largely representing distinctions within the population (e.g., tribal (tribe) affiliations). In the south, under the British, there had been a major distinction regarding administrative autonomy and political influence between the city of Aden (governed directly from London via the colonial office) and the hinterland, which was divided into more than 20 “statelets,” many of which were clearly associated with ancient tribal groupings of one form or another. In order to break down the old tribal affiliations and the associated economic and political factionalism, the postindependence government abolished these traditional units and reorganized the country into governorates (muḥāfaẓāt).

United Yemen eventually embraced a system based, as in South Yemen, on a series of governorates—20 in total, not counting Sanaa, which forms its own unit. The governorates are in turn divided into several hundred districts. The governors of the governorates are appointed by the federal president, but each jurisdiction has its own elected council. An important issue that remains to be resolved is the amount of authority that the governorates will have in the federal system. The trend in both the north and the south was to provide the governorates with a high degree of autonomy. The first municipal elections under the Local Authority Law (1999) were held in 2001. However, Yemen has lacked the infrastructural resources to conduct efficient local elections, and safeguards providing protection from the interference of the central government have been slow to materialize.

The two parts of the new state had markedly contrasting legal traditions. In the north the legal system had been a mix of Sharīʿah (Islamic law) and ʿurf (tribal custom). In the south the legal system was a mixture of Sharīʿah in matters of personal status (e.g., marriage, divorce, inheritance) and British commercial and common law (modified to suit the needs of the Marxist government) and, in rural areas, a combination of Sharīʿah and ʿurf.

New legal codes were promulgated in 1991–94. Each district has a court of first instance, and each governorate has a court of appeals; the Supreme Court is located at the capital. These courts have full competency to hear all civil and criminal cases. The Supreme Judicial Council oversees the court system. There are a number of specialized courts. Under the constitution, Sharīʿah is the source of all legislation.

There are a number of active political parties at the national level, but the composition and membership of political parties are regulated by law. Parties based on such factors as regional, tribal, sectarian, or ethnic persuasion are expressly prohibited. Each party must seek a license from a state committee to legally exist. The most successful party by far is the General People's Congress; other parties include Iṣlāḥ (the Yemeni Congregation for Reform), the Nasserite Unionist Party, and several socialist organizations.

The combined armed forces of Yemen, including army, air force, and navy, are small and poorly equipped by the standards of the region. Since the unification of the state in 1990, the manpower of Yemen's conventional army has suffered a general decline. The extensive inventories of Eastern-bloc weapons that the country inherited rapidly became dated, and many weapons systems were discarded. The military consists of volunteers serving two-year enlistments, and there is no consistent military educational or professional development system or enlisted personnel or officers. Military strength has been augmented by a large number of paramilitary forces, mostly associated with the Ministry of the Interior. Also, there are a relatively small number of reservists and tribal levies that the government can call on in times of emergency.

Military officers have often involved themselves in political affairs: in the north the military played the dominant role in the political system following the overthrow of the civilian government by Col. Ibrāhīm al-Ḥamdī in 1974. Internal security is a major concern of the government. The Political Security Organization is the major intelligence organ of the state; police and paramilitary groups provide security, and the Criminal Investigation Department conducts criminal investigations.

Despite the generally healthy climate of the Yemeni highlands, where most of the population live, the standard of public health remains very low. Contributing factors include: (1) unsanitary water supplies, (2) numerous cultural patterns that compromise both personal and group hygiene, (3) the presence of numerous diseases at endemic rates (e.g., malaria in the coastal belt and gastroenteritis in the highlands), (4) the very high birth rate, and (5) insufficient personnel and financial resources to provide modern medical care and to undertake any massive public health programs. There are various programs supported and operated by foreign donors that address these needs to some degree. Sanaa and Aden have numerous hospitals, but few meet Western standards of sanitation and medical practice.

Modern systems of education were established in both Yemens during the 1960s, but limited resources and a high birth rate ensured that education continued to reach only a fraction of school-age children. For a variety of social and cultural reasons, certain subgroups of the school-age population—most notably girls—remained underrepresented in the system. Despite the dramatic expansion of teacher training, the lack of adequately qualified Yemeni teachers was a major problem in the north; Egyptian and other Arab expatriates largely filled this void. The overall literacy rate remains relatively low, and the disparity between males and females is large. More than two-thirds of men and less than one-third of women are literate. Partly because of an inadequate infrastructure that includes classroom shortages and poor materials and facilities, only a portion of eligible children enroll in school. Among those who do attend, only a small fraction go on to complete secondary education.

Higher education is limited to a very small minority. The University of Sanaa (founded 1970), established largely with grants from Kuwait, is coeducational and comprises a variety of specialized colleges—e.g., those of agriculture, medicine, commerce, and law. The University of Aden (1975) offers a similar array of specialties. These two senior institutions of higher learning have spawned universities and colleges throughout Yemen, and there are now several small colleges as well as vocational and polytechnic institutes in the larger urban centres that provide training in a variety of fields. However, wealthy families typically send their children abroad for higher education.

In addition, both of the major Muslim sects operate religious institutes for the preparation of judges and other religious personnel, although this often requires additional study at such well-known institutions as al-Azhar University (Azhar University, al-) in Cairo. By the early 21st century the number of small religious schools associated with foreign Islamic groups had proliferated. Several thousand small religious academies were closed in 2005, and all non-Yemenis matriculating in unregistered schools were asked to leave the country for fear such institutions were involved in religious extremism.

Yemen is a part of the Islamic world and as such reflects many of the contemporary trends in Islam. Most Yemenis are Muslim and are tolerant of non-Muslims as well as of the various branches of Islam. While proud of their Islamic heritage, Yemenis are also intensely proud of their pre-Islamic history, including that of the Sabaʾ and Ḥaḍramawt kingdoms. In their extensive networks of overland and maritime trade, the ancient Yemenis encountered myriad cultures and civilizations. There is ample evidence of Greek, Roman, Indian, Indonesian, and Chinese influence on various aspects of both traditional and contemporary Yemeni culture. Similarities have been drawn, for example, between marriage institutions in India and Yemen and between religious music in Yemen and Byzantine masses.

Yemen shares in many of the customs and lifeways that are found in other parts of the Arab world. Culture is intensely patriarchal (patriarchy), and households usually consist of an extended family living in a single domicile or family compound. The head of the family is the eldest male, who makes all significant decisions for the family and its members. Women play a secondary role in running the household and raising the children and, in rural areas, helping to work the family farm. Though nearly one-fourth of Yemeni women obtain work outside the home, a woman traditionally earns most of her social status through bearing children, particularly males. The birth of a male child is considered one of the most important social events in Yemeni society and is followed almost immediately by a circumcision ceremony. Though prohibited by law in 2001, female genital cutting still occurs, taking place primarily in private and varying significantly by region.

Marriages (marriage) are almost always arranged and frequently are undertaken at a young age. Although the opinion of a potential bride or groom might be solicited on the issue, the final decision on marriage belongs with the head of the household. As in many parts of the Islamic world, endogamy (the practice of marrying someone from within one's own kin group) is common, the preferred marriage being with a paternal first cousin of the opposite gender. The practice of mahr (bride-price, given by the father of the groom) is a usual part of the marriage ceremony. Divorce is not common, but neither is there a stigma attached to it. Men may have as many as four wives at the same time, though in practice it is rare for a man to take more than one wife.

Yemeni society is tribally (tribe) based, and trust and assurance most often are measured by degree of consanguinity. Families are very close and are the focus of the individual's primary devotion; one's second allegiance is to the tribe, an extended family unit that ordinarily traces its ties to a common eponymous ancestor. In rural Yemen, state authority is weak, and disputes between tribes are frequently solved through violence. The art of the feud is still quite real, and, as a consequence, Yemen is a gun culture. Virtually every household has at least one weapon, and men and boys often carry firearms in public. Even when not carrying a pistol or a rifle, most Yemeni males—particularly those belonging to a rural tribe—will carry a dagger, the traditional janbiyyah or jambiyyah, a short, broad, curved blade sheathed on a belt worn across the abdomen and serving as a signal of one's status within social and tribal hierarchies.

The traditional nature of Yemeni society is reflected in choices of attire, though the native dress of Yemen differs somewhat from that found in other conservative parts of the Arabian Peninsula. Men sometimes wear the full-length, loose-fitting thawb—frequently with a jacket over it—but more often the traditional fūṭah, a saronglike wraparound kilt, is worn with a shirt. The turban is a common type of head covering, and a finely woven bamboo hat (shaped somewhat like a fez) called a kofiya (or kofia) is a more formal choice of headgear. There are various forms of dress for women, depending on the social role a woman plays and where she lives. Throughout the country, women wear clothing that covers the entire body: arms, legs, and hair are not exposed. In the city, dress tends to be of darker colours, and, when a woman goes outside of the home, she wears some sort of overgarment; this may range from the complete coverage of a burka to an overcoat-like balṭō to a ḥijāb, a head scarf. In addition, some women may attach a niqāb, a veil covering the face, to the head scarf. An outer garment, such as another scarf or shawl, may be worn as well. In the countryside, clothing for women tends to be somewhat more utilitarian and may consist of a dress or robe that provides for a greater range of movement and under which, in some parts of Yemen, it is not uncommon for a woman to wear a pair of loose slacks known as a sirwāl. Also in the countryside, a woman's face may or may not be covered, and dresses are sometimes sewn from brightly coloured fabric. Working women frequently wear a broad-brimmed straw hat (dhola) to ward off the sun.

Traditional Yemeni cuisine is broadly similar to that found in other areas of the Arabian Peninsula, but it is also heavily influenced by the cuisine of eastern Africa and South Asia. The major meats are chicken, mutton, and goat. Other staples include potatoes, onions, and tomatoes. There are several types of bread; unleavened flat bread is typical. A popular dish in Yemen is saltah, a stew of lamb or chicken that is heavily spiced with fenugreek and other herbs. Tea is a common drink, and coffee is very popular. Alcoholic beverages are considered culturally and religiously inappropriate, though they are available.

Unquestionably the most important and distinctive social institution and form of recreation in Yemen is the khat party, or khat “chew.” This is especially true in the northern part of the country, but, since the slight increase in general prosperity in the 1970s, the use of khat has spread to virtually all levels of Yemeni society. At least half of all men, and a smaller number of women, attend khat chews (which usually are segregated by gender) with some regularity, and many do so on a daily basis. Khat chews usually begin in the early afternoon after the main meal of the day, and they often go on until the early evening. Much gets done at these pleasurable sessions: gossip is exchanged, serious matters are discussed and debated, political and business decisions are made, business is transacted, disputes and grievances are settled, Yemeni history and lore are passed on, and music and poetry are played and recited.

Yemenis celebrate the traditional Islamic holidays, including Īd al-Aḍḥāʿ (marking the culmination of the hajj rites near Mecca) and Īd al-Fiṭrʿ (marking the end of Ramadan), as well as the Prophet Muhammad's birthday. Shīʿites observe Āshūrāʾʿ (commemorating the death of al-Ḥusayn ibn ʿAlī, the Prophet's grandson). The Day of National Unity is May 22, the day on which, in 1990, North Yemen and South Yemen were officially united. A number of other civil and religious holidays also are observed.

The most widespread and traditional cultural outlet is oral, in the form of proverbs, popular stories, and poetry; poems that deal with timeless themes such as love and death as well as with Yemeni history, biography, and Islamic themes and traditions are particularly prevalent. Yemen is an integral part of contemporary Arab trends in literature, political essays, and scholarly writing; Yemeni poets, past and present, are among the most esteemed in the Arab world. Similarly, the songs and singers of Yemen are highly respected, and some Yemeni instruments (such as the lutelike qanbus, or ṭurbī, now largely replaced by the ʿūd) and genres (such as al-ghināʾ al-ṣanʿānī, or Sanaani song) are quite unique.

Dances, performed with or without musical accompaniment, are a feature of weddings and other social occasions; these are performed by men and women separately. The male dances are often performed with the janbiyyah dagger.

The General Organization of Antiquities and Museums administers the major cultural institutions. Most institutions are located in the larger cities. The national museum in Sanaa and the archaeological museum in Aden house important treasures from the pre-Islamic period. The Military Museum is located in Sanaa. There are also military and folk museums in Aden.

Organized sports fall under the auspices of the Ministry of Youth and Sports. North Yemen first appeared in Summer Olympic competition in 1984 and South Yemen in 1988; the unified country has sent teams to the Summer Games since 1992. Two Yemeni boxers living abroad enjoyed great success: Naseem Hamed, a British boxer of Yemeni ancestry, held the world featherweight title during the late 1990s and early 21st century; and Isra Girgrah, a female boxer born in Yemen and fighting out of the United States, held several lightweight belts during that same period.

Through its control of the media, education, and trade, the socialist government of the south severely restricted the participation of its population in both regional and global cultural trends during its most ascetic period, extending from the mid-1970s to the mid-1980s. The northern government correspondingly exercised certain restrictions in order to protect itself from the influence of the socialist south and from other challenges to the reigning political and cultural norms. In both Yemens, newspapers and magazines were closely censored, and radio and television were monopolized by the state.

These conditions changed drastically with the merger in 1990. Since that time, more than 85 newspapers and journals—representing divergent points of view and a wide range of political, social, economic, and cultural organizations—have come into being. The national television and radio networks, although still operated by the government, are less strictly controlled than before unification.

The Romans (ancient Rome) began expanding their power and influence to the Red Sea in the 1st century AD and soon learned the secrets of the Yemeni traders—namely, the true source of luxury commodities provided by the Yemenis and how to exploit the monsoon winds to traffic between Red Sea ports and those of southern Asia and eastern Africa, where these treasures could be found. It was only a matter of time before Yemen, unable to compete effectively against imperial Rome, went into economic decline, and the subsequent loss of revenue made it impossible for Yemen to maintain its extensive cities and attendant facilities. The most famous instance was the failure to maintain the Great Dam at Maʾrib—the heart of a monumental irrigation project and one of the engineering marvels of the ancient world. Its rupture sometime in the 6th century AD constitutes the symbolic end to the long era of the Yemeni trading kingdoms.

The Ḥimyarites grew resentful of the Aksumites, who they came to view as usurpers, and sought the support of the Sāsānian dynasty of Persia to expel them. By obliging, the Persians added the satrapy of Yemen to their domains. The last Persian governor of Yemen apparently converted to Islam in AD 628, accepting the political dominance of the Muslim community.

Islam spread readily and quickly in Yemen, perhaps because of the century of economic decline and the atrocious behaviour of both Jews and Christians during that time. The Prophet Muhammad sent his son-in-law as governor, and two of Yemen's most famous mosques—that in Janadiyyah (near Taʿizz) and the Great Mosque in Sanaa (said to have incorporated some materials from earlier Jewish and Christian structures)—are thought to be among the earliest examples of Islamic architecture.

Despite the fact that Muhammad's first successor, the caliph Abū Bakr (served 632–634), managed to unify the Arabian Peninsula, it was not long before Yemen once again demonstrated its fractious nature. Often when the caliph sent a representative to put down rebellions or deal with other problems, the representative would establish his own dynasty. Such was the case with Muḥammad ibn Ziyād, who early in the 9th century founded the city of Zabīd as his capital. (See Ziyādid Dynasty.)

For the history of Yemen, however, the most important event after the triumph of Islam was the introduction in the 9th century of the Zaydī (Zaydīyah) sect from Iraq—a group of Shīʿites who accepted Zayd ibn ʿAlī, a direct descendant of Muhammad, as the last legitimate successor to the Prophet. Much of Yemeni culture and civilization for the next 1,000 years was to bear the stamp of Zaydī Islam. That same span of time was host to a confusing series of factional, dynastic, local, and imperial rulers contesting against one another and against the Zaydīs for control of Yemen. Among them were the Ṣulayḥids (Ṣulayḥid dynasty) and the Fāṭimids (Fāṭimid Dynasty), who were Ismāʿīlīs (another Shīʿite branch); the Ayyūbids (Ayyūbid dynasty); and the Rasūlids (Rasūlid dynasty), whose long rule (13th–15th century) firmly established Sunnism in southern and western Yemen.

Yemen next appeared on the world stage when, according to one account, the leader of a Sufi religious order discovered the stimulating properties of coffee (coffee production) as a beverage, probably about the beginning of the 15th century. As a result, Yemen and the Red Sea became an arena of conflict between the Egyptians, the Ottomans, and various European powers seeking control over the emerging market for Coffea arabica as well as over the long-standing trade in condiments and spices from the East; this conflict occupied most of the 16th and 17th centuries. By the beginning of the 18th century, however, the route between Europe and Asia around Africa had become the preferred one, and the world had once again lost interest in Yemen. In the meantime, the coffee plant had been smuggled out of Yemen and transplanted into a great variety of new and more-profitable locales, from Asia to the New World. The effect of the redirection of trade was dramatic: cities such as Aden and Mocha (as the name would suggest, once a major coffee centre), which had burgeoned with populations in excess of 10,000, shrank to villages of a few hundred.

The north became independent at the end of World War I in 1918, with the departure of the Ottoman (Ottoman Empire) forces; the imam of the Zaydīs, Yaḥyā Maḥmūd al-Mutawwakil (Yaḥyā), became the de facto ruler in the north by virtue of his lengthy campaign against the Ottoman presence in Yemen. In the 1920s Imam Yaḥyā sought to consolidate his hold on the country by working to bring the Shāfiʿī areas under his administrative jurisdiction and by suppressing much of the intertribal feuding and tribal opposition to the imamate. In an effort to enhance the effectiveness of his campaigns against the tribes and other fractious elements, the imam sent a group of Yemeni youth to Iraq in the mid-1930s to learn modern military techniques and weaponry. These students would eventually become the kernel of domestic opposition to Yaḥyā and his policies.

Yemeni independence allowed the imam to resuscitate Zaydī claims to “historic Yemen,” which included Aden and the protectorate states, as well as an area farther north that had been occupied only recently by an expanding Kingdom of Saudi Arabia (Saudi Arabia), including the province of Asir and some important areas around the Najrān oasis and Jīzān. These areas became a point of conflict with the house of Saʿūd. Yaḥyā, of course, did not recognize the standing Anglo-Ottoman border agreement.

The British (British Empire), on the other hand, retained control over the south, which they considered strategically and economically important to their empire. Friction between the imamate and Britain characterized the entire interwar period, as Imam Yaḥyā sought to include the south in the united Yemen that he perceived to be his patrimony. The British in the meantime were consolidating their position in the south. The most important change was the incorporation of the Ḥaḍramawt and its great valley into the protectorate system—the result of the labours of British diplomat Harold Ingrams, who negotiated the famous “Ingrams's Peace” among the more than 1,400 tribes and clans that had been feuding in that district for decades.

By the end of World War II in 1945, dissatisfaction with Yaḥyā and his imamate had spread to a rather wide segment of Yemeni society, including both secular and Muslim reformers and modernists, other elements of the traditional elite, and even the ʿulamāʾ (religious scholars). This tide of dissent culminated in early 1948 in the assassination of Yaḥyā and a coup by a varied coalition of dissidents. Much to the consternation of the plotters, however, Yaḥyā's son Aḥmad succeeded in bringing together many of the tribal elements of the north, overthrew the new government, and installed himself as imam. Although Imam Aḥmad ibn Yaḥyā had indicated that he supported many of the popular political, economic, and social demands (e.g., creation of a cabinet with real responsibilities, abandonment of the principle of economic autarky, and the establishment of free public education), his own government soon resembled his father's in nearly all respects. An attempt on Aḥmad's life in 1955 only increased repression; indeed, his paranoia concerning the loyalty of major tribal elements prompted actions that eventually cost his son tribal support during the civil war after the 1962 revolution.

In the meantime, the policies of both imams had backfired in the south. Although they had the advantage of offering an indigenous Muslim regime as an alternative to secular British rule, the imams' aggressive policies had alarmed many of the ruling families of the statelets in the south. The latter now believed, probably correctly, that, if their small statelets were to be taken over by the imam, their perquisites and status would be curtailed if not eliminated. Consequently, most deemed it advantageous to cooperate more closely with Britain, which, after all, subsidized them and implied a role for them in future arrangements. By the late 1950s an earlier proposal to federate some of the smaller statelets had grown into a much broader scheme to include all the principalities and sheikhdoms in a larger political entity that would eventually achieve independence.

Britain's insistence that Aden be a part of the new entity created the anomaly that eventually killed the plan. The sophisticated business community, the activist trade unions, and other similarly modern political and social organizations in Aden feared for their future at the hands of what they perceived to be a group of largely illiterate and parochial tribal leaders from the backward rural protectorates. The tribal leaders, on the other hand, feared at worst their overthrow or at best a degree of political and economic participation severely limited by an Adeni population that included some non-Muslims and many non-Arabs.

The British continued to insist upon their chosen course of action, and by 1965 all but 4 of the 21 protectorate states had joined the Federation of South Arabia. Shortly thereafter, Britain announced that it would leave southern Arabia and that independence would ensue no later than 1968. This announcement unleashed the violent political conflict that prevailed in Aden and the protectorates for the next two years as sundry organizations fought for control of the destiny of South Yemen.

In the north, meanwhile, Aḥmad died of natural causes in September 1962, and his son Muḥammad al-Badr became imam. Within a week, elements of the military, supported by a variety of political organizations, staged a coup and declared the foundation of the Yemen Arab Republic (North Yemen). The young imam escaped from his battered palace, fled into the northern highlands, and began the traditional process of rallying the tribes to his cause. The new republic called upon Egypt for assistance, and Egyptian troops and equipment arrived almost immediately to defend the new regime of ʿAbd Allāh al-Sallāl, the nominal leader of the 1962 revolution and the first president of North Yemen. Nearly as quickly, Saudi Arabia provided aid and sanctuary to the imam and his largely tribal royalist forces.

The establishment of a republic in North Yemen provided a tremendous incentive to the elements in the south that sought to eliminate the British presence there. Furthermore, the Egyptians agreed to provide support for some of the organizations campaigning for southern independence—e.g., the Front for the Liberation of (Occupied) South Yemen (FLOSY). However, not all elements in either of the two Yemens were sympathetic to Egyptian policies, much less to the dominant role that Egypt had begun to play in southern Arabia. A new, radical alternative movement, the National Liberation Front (NLF), drew its support primarily from indigenous elements in the south. As the time for independence drew near, the conflict between the various groups, and especially between the NLF and FLOSY, escalated into open warfare for the right to govern after British withdrawal. By late 1967 the NLF clearly had the upper hand; the British finally accepted the inevitable and arranged the transfer of sovereignty to the NLF on Nov. 30, 1967.

The new government in Aden renamed the country the People's Republic of South Yemen. Short of resources and unable to obtain any significant amounts of aid, either from the Western states or from those in the Arab world, it began to drift toward the Soviet Union (Union of Soviet Socialist Republics), which eagerly provided economic and technical assistance in hopes of bringing an Arab state into its political sphere. By the early 1970s South Yemen had become an avowedly Marxist state and had inaugurated a radical restructuring of the economy and society along communist lines, renaming itself the People's Democratic Republic of Yemen.

In North Yemen the conflict between the imam's royalist forces and the republicans had escalated into a full-blown civil war that continued fitfully and tragically until 1970. Participation, however, was not limited to the Yemenis: Saudi Arabia, Iran, and Jordan supported the royalists, whereas Egypt and the Soviet Union and other Eastern-bloc states supported the republicans. Britain and the United States, as well as the United Nations, also eventually became major players, even if only at the diplomatic level. By the late 1960s, however, the Yemenis decided that the only logical outcome of the conflict was a compromise, which would have as its most important side effect the departure of the various foreign forces. Al-Sallāl's pro-Egyptian regime was ousted in a bloodless coup in 1968 and replaced by a nominally civilian one headed by Pres. ʿAbd al-Raḥmān al-Iryānī. Two years later, with the blessing of the two major foreign participants—Egypt and Saudi Arabia—the leaders of North Yemen agreed upon the Compromise of 1970, which established a republican government in which some major positions were assigned to members of the royalist faction. It was agreed that the imam and his family were not to return to Yemen or to play any role whatsoever in the new state; accordingly, the imam went into exile in Britain and died there in the late 1990s.

The compromise government embarked haltingly upon a program of political and economic development, with few resources and even fewer skilled personnel to implement the desired changes. Impatient, the military and some tribal elements dismissed the civilian cabinet in 1974 and replaced it with a military-led Command Council headed by Ibrāhīm al-Ḥamdī, who appointed a cabinet largely composed of technocrats. That government slowly but surely began to build a set of more-modern institutions and to implement the beginnings of a program of development—at the local as well as the national level. Not all sectors of the population, however, accepted the government's new powers and influence over traditional political, economic, and social relationships. A clear indication of this discontent was the assassination of two presidents in succession (al-Ḥamdī in 1977 and, only eight months later, Aḥmad al-Ghashmī in 1978). The People's Constituent Assembly, which had been created somewhat earlier, selected Col. ʿAlī ʿAbd Allāh Ṣāliḥ (Ṣāliḥ, ʿAli ʿAbd Allāh) as al-Ghashmī's successor. Despite early public skepticism and a serious coup attempt in late 1978, Ṣāliḥ managed to conciliate most factions, to improve relations with Yemen's neighbours, and to resume various programs of economic and political development and institutionalization. More firmly in power in the 1980s, he created the political organization that was to become known as his party, the General People's Congress (GPC), and steered Yemen into the age of oil.

Now that the two Yemens were independent, expectations rose in some quarters that there would be some form of unification, especially since both states publicly claimed to support the idea. Such was not forthcoming, however, the primary reason being the drastic divergence of political and socioeconomic orientations of the two regimes by the end of the 1960s. Whereas the north elected to remain a mixed but largely market economy and to retain ties with the West as well as with Saudi Arabia, the south began to move rapidly in a socialist direction under the leadership of the more radical wing of the NLF.

Political differences led to a brief border war between the two Yemens in 1972. Notwithstanding efforts by some Yemenis and by others to resolve these disputes—indeed, despite the first of two aborted agreements to unify—the basic conflicts appeared irreconcilable. The South Yemenis perceived their cause, that of Marxist transformation of the Arab political, economic, and social systems, to be in desperate need of direct action. In fact, South Yemen helped to instigate and fund a broad-based opposition movement in the north, the National Democratic Front, in the mid-1970s; elements of the leadership sanctioned the assassination of the North Yemeni president, al-Ghashmī, in 1978. At the same time, South Yemen supported other revolutionary organizations in the region, such as the Popular Front for the Liberation of Oman. The continuing friction between the two Yemens led to another brief but more serious border war in 1979; as in the previous case, that conflict was followed by a short-lived agreement to unify.

All the while, however, significant fissures—both ideological and practical—were opening in South Yemen within the ruling Yemen Socialist Party (YSP), the party that evolved out of the NLF. ʿAbd al-Fattāḥ Ismāʿīl was the major ideologue of the YSP, as well as head of state and the driving force behind South Yemen's move toward the Soviet Union earlier in the 1970s. Late in that decade, he was opposed by his former ally and leader of the “Chinese faction” in the regime, South Yemen president Sālim ʿAlī Rubayyī, whose visit to China inspired his politics with Maoist ideas. The conflict ended in Rubayyī's execution on charges that he had been behind the assassination of al-Ghashmī.

In turn, Ismāʿīl proved too dogmatic and rigid—in his analyses, policies, and methods of implementation—and was deposed in 1980. His successor, ʿAlī Nāṣir Muḥammad, instituted a far less dogmatic political and economic order. In January 1986 the various personal and ideological differences surfaced briefly in an episode of violent civil strife that left Ismāʿīl and many of his supporters dead, resulted in the exile of ʿAlī Nāṣir Muḥammad, and brought to power a group of moderate politicians and technocrats led by ʿAlī Sālim al-Bayḍ and Ḥaydar Abū Bakr al-ʿAṭṭas. It was this element of the YSP that undertook the negotiations that brought about the unity of the two Yemens. The ability of the new leadership to build popular political support and to revive the faltering development of South Yemen was tested in the late 1980s—and it was found wanting.

Two factors made the unity agreement of 1990 possible: (1) the discovery of oil (petroleum) and natural gas in both countries at roughly the same time and in roughly the same geographic region (from Maʾrib to Shabwah), some of which was in dispute between them (clearly, it would not have been in the best interest of either country to engage in a costly conflict over such important resources; it made far more sense to unite and share the profits to be gained from a rational exploitation of the deposits), and (2) the decision by Mikhail Gorbachev (Gorbachev, Mikhail), then president of the Soviet Union, to abandon that country's support of the governments and policies of a number of eastern European states, some of which were South Yemen's principal sources of financial, technical, and personnel assistance. Once the communist bloc gave way to popular democratic movements, it was only a matter of time before the isolated South Yemeni regime would crumble. The rational option for the YSP—and the one it chose—was to enter into negotiations with North Yemen while still in power.

Inasmuch as the border wars of 1972 and 1979 each had concluded with unification agreements that, unsurprisingly, were aborted in a matter of months, the decision by the two ruling parties in late November 1989 to unify the two states—and, more importantly, its actual implementation six months later—took many Yemenis and nearly all outside observers by surprise. Whereas South Yemen had taken the lead in the past, this effort to unify was initiated and pushed by the Ṣāliḥ (Ṣāliḥ, ʿAli ʿAbd Allāh) regime of North Yemen. Adopted by the legislatures of the two Yemens on May 22, 1990, the constitution of the new republic was declared in effect on that date.

The final terms of unification called for the full merger of the two states and the creation of a political system based on multiparty democracy. Sanaa was declared the political capital, and Aden was to be the economic capital. After a 30-month transition period, elections of a new national legislature were to take place in November 1992 (although ultimately they would be postponed). During the transition period, the two existing legislatures would meet together as a single body, and all other offices and powers would be shared equally between the two ruling parties, the GPC and the YSP. Ṣāliḥ was to serve as interim president of the republic and al-Bayḍ, the secretary-general of the YSP, was to be vice president.

Efforts by the Ṣāliḥ government to strengthen and build support and legitimacy for the political system of united Yemen were sorely compromised by an environment marked by severe economic collapse and widespread deprivation, especially since these conditions came quickly after a period of improving economic conditions and soaring expectations. Most of the population in the northern part of Yemen had experienced better living conditions in the 1980s, if not before, and the prospects of oil revenues and the reputed benefits of unification had greatly raised expectations in both parts of Yemen at the end of the 1980s.

The indirect cause of the collapse of the Yemeni economy can be found in the Persian Gulf War (1990–91), which followed Iraq's invasion and occupation of Kuwait in August 1990. The growing importance of oil revenues notwithstanding, the Yemeni economy in the late 1980s remained heavily dependent on workers' remittances and external economic aid from Saudi Arabia and, to a lesser extent, the other oil-rich Persian Gulf states. In the fall of 1990, the newly created Republic of Yemen took the position that a diplomatic solution for Iraq's aggression should be reached between the Arab countries. Yemen's refusal to join the U.S.-Saudi military coalition against Iraq prompted Saudi Arabia to expel several hundred thousand Yemeni workers and to cut all foreign aid to Yemen; most of the other Arab oil states followed suit. Within months, the republic's gross domestic product and government revenues—to which external aid contributed significantly—plunged; the unemployment and inflation rates, as well as the budget deficit, soared. By 1992, general contraction of the economy had produced widespread and deepening privation, and modest increases in oil revenues did not add much to the capacity of the new government to ease the growing suffering and to stem the collapse of the economy.

With the economy ailing, spats of political violence, including bombings and assassinations, marred the years leading to the republic's first general parliamentary elections. Despite the growing acrimony, however, the unification regime was able to pull back from the political brink and hold the prescribed legislative elections in April 1993, only a few months later than originally planned; they were judged by international monitors to be relatively free and fair. President Ṣāliḥ's party, the GPC, emerged with a large plurality of seats. The Islamic Reform Grouping (Iṣlāḥ), the main organized opposition to the unification regime since 1990, and the YSP both won strong minority representation. Holding virtually all the seats, the three parties formed a coalition government in May 1993, amid some hope that the political crisis had passed.

Instead, the conflict between the political leaders of the northern part of Yemen and those of the south worsened dramatically in the second half of 1993 and the early months of 1994. For the second time in little more than a year, Vice President al-Bayḍ left Sanaa and retired to Aden, taking many of his YSP colleagues with him. Despite major efforts at reconciliation, from within and without Yemen, the political struggle escalated into armed conflict in the spring of 1994, and YSP leaders and other southern politicians—still in control of their armed forces—resorted to armed secession in the early summer of that year. The Yemeni civil war of 1994, lasting from May to early July, resulted in the defeat of the southern armed forces and the flight into exile of most of the YSP leaders and other southern secessionists.

The short civil war left the YSP in political shambles and left control of the state in united Yemen in the hands of a GPC-Iṣlāḥ coalition dominated by Ṣāliḥ. Over the next few years, the effort to reorganize politics and to strengthen the voice of the south in Yemen's political life was hampered by the inability of the YSP to resuscitate itself; at the same time, strained relations within the GPC-Iṣlāḥ coalition led to increasing dominance by the GPC and to an oppositional stance on Iṣlāḥ's part. The political conflict and unrest that accompanied and followed the civil war led to a revival of the power of the security forces and to the curtailment of the freedom of opposition parties, the media, and nongovernmental organizations, although, by the turn of the 21st century, democracy and human rights were more secure than they had been in either of the two Yemens. Human rights were being violated, but those violations were protested with increasing success by groups within Yemen.

Yemen held its second parliamentary election on April 27, 1997. The GPC won a majority of the seats, and Iṣlāḥ finished second; when a number of successful independent candidates joined those two parties after the election, their respective seats were increased. Ṣāliḥ continued as president, and in September 1999 he was returned to office in the country's first direct presidential elections.

Externally, Yemen settled two major border disputes. In 1998 a violent conflict with Eritrea over ownership of the Ḥanīsh Islands in the Red Sea was settled in Yemen's favour after international arbitration. Two years later Yemen and Saudi Arabia settled the long-standing and contentious disagreement over their mutual border.

At home, huge revenues from the extraction and sale of petroleum stabilized the economy, but internal security remained elusive. During the 1990s, tribal groups seeking money or endeavouring to gain leverage in political disputes against the central government kidnapped scores of foreigners, including many tourists. At the same time, numerous Sunni Islamist groups gravitated to Yemen, particularly to tribal areas where the authority of the central government was weak, and preaching and teaching at many Yemeni mosques and madrasas (religious schools) took on a clearly anti-American tone. In 2000 Muslim militants associated with the al-Qaeda (Qaeda, al-) organization bombed (terrorism) the U.S. warship Cole in Aden's harbour. The group, whose leader Osama bin Laden (bin Laden, Osama) was of Yemeni ancestry, enjoyed substantial support among Yemeni Islamists. Following the September 11 attacks on the United States in 2001, the Ṣāliḥ government moved against al-Qaeda by arresting dozens of militants and freezing assets of those believed to have supported the organization.

Parliamentary elections held in 2003 reaffirmed the majority of the GPC, who seemed to benefit from fragmentation among the many smaller opposition parties. In 2004 a Zaydī rebellion protesting the government's close ties with the United States erupted in extreme northwestern Yemen. The rebels sought a return of the imamate, and, although their leader, Ḥusayn al-Hawthī, was killed at the end of the year, the rebellion continued. In 2006 Ṣāliḥ was elected to a second seven-year term as president.