count of Hainaut (1280–1304) and of the Dutch provinces of Holland and Zeeland (1299–1304), who united the counties and prevented the northward expansion of the house of Dampierre, the counts of Flanders.

Eldest son of John of Avesnes, count of Hainaut, and Alida, sister of Count William II of Holland, John secured the title count of Hainaut in 1280 as John I. Long a friend of King Philip IV the Fair of France, the Count influenced his cousin, Count Floris V of Holland, to end his long, friendly relations with King Edward I of England and make an alliance with France, an action that was violently opposed by several Dutch nobles, who seized and murdered Floris (June 27, 1296).

John was then named governor of Holland and guardian of Floris' 15-year-old son, after whose death (1299), he became count of Holland as John II. Though the people of Holland accepted his leadership, he had to ward off a challenge by King Albert I of Germany (1300), repel an invasion by English forces (1300?), subdue a rebellion in Zeeland (1301), and fight the army of the Dampierres for two years before driving the Flemish from Holland and Zeeland in 1304.

duke of Brittany (from 1286) and count of Richemont, son of John I. He accompanied his father on St. Louis's crusade to Tunisia (1270) and fought also in Palestine. He returned to Europe in 1272 and, in subsequent years, shifted repeatedly from one side to another in the wars between Edward I of England and Philip IV of France, who made him a peer of France (1297). His son, Arthur II, succeeded him.

king of Aragon (1458–79) and also king of Navarre (1425–79); he was the instigator of the union of Castile and Aragon through the historic marriage of his son Ferdinand with Isabella of Castile.

John was a younger son of Ferdinand of Antequera, elected king of Aragon (as Ferdinand I) in 1412. John and his brothers retained their positions and revenues in Castile, and he married Blanche, the heiress to Navarre, of which he claimed the kingship (1425–79). On his wife's death, he married Juana Enriques, daughter of the admiral of castile (1447), whose ambitions led to a conflict between John and his eldest son by his first marriage, Charles, prince of Viana.

In 1458 John succeeded his elder brother Alfonso V as king of Aragon, with Sicily and Sardinia. He was blamed for the mysterious death of his son Charles, who had a strong following in Catalonia, where John's policies were deeply resented. The Catalans offered the crown to Peter of Portugal, who died, after which they appealed to the French for aid. In October 1469 John arranged for his son by his second marriage, Ferdinand (Ferdinand II), to marry Isabella (Isabella I), the recognized heiress to Castile, despite the opposition of her brother, Henry IV of Castile. This marriage led to the union of Castile and Aragon and the creation of the modern state of Spain. In Aragon, John's rule deepened the rift between Aragon proper and Catalonia.

king of Castile from 1406 to 1454; his political weakness led him to rely on his favourite, Álvaro de Luna (Luna, Álvaro de), whom he made constable. He was nevertheless considered a man of cultivated taste and a patron of poets.

John succeeded his father, Henry III, as an infant of less than two years of age, under the joint regency of his mother, Catherine of Lancaster, and his uncle, the infante Ferdinand, who became king of Aragon (as Ferdinand I) in 1412. John took the reins in 1419 but soon placed himself in the hands of his companion Luna, who contested the influence of Ferdinand's sons in Castile. This led to factional struggles among the nobles, during which Luna enriched himself and his supporters. In 1430 a settlement was reached, and John II led a campaign against Granada, defeating the Muslims in the Battle of Higueruela (1431). John II sequestered his son, the future Henry IV, at Segovia, giving rise to fresh rivalries. He and Luna vanquished the dissidents at the Battle of Olmedo in 1445.

In 1447 Luna persuaded John, now a widower, to marry Isabella of Portugal, who soon opposed him. After Luna had connived at a murder, the tide turned; and in 1453 John II was persuaded to arrest and execute his favourite. He proved unable to govern alone.

During John's reign the revival of learning had its effect on the culture of the court and nobility. The King protected the poet Juan de Mena and encouraged other writers.

After becoming king on Aug. 22, 1350, John continued a truce with the English until later that year, when he had an English hostage, Raoul de Brienne, comte d'Eu, former constable of France, executed. By March 1351 King Edward III of England realized the impossibility of remaining at peace; but John committed the first act of hostility by attacking and recapturing Saint-Jean-d'Angély in western France that September 7. John signed a new truce with England on Sept. 12, 1351, but broke it by supporting the partisans of Charles of Blois (a pretender to Brittany, then held prisoner by Edward) in August 1352; the peace, however, was extended until September 23.

John's other bitter enemy was Charles II the Bad, king of Navarre, to whom John gave his daughter Joan as an offer of alliance; the enmity still remained strong, however, because John never paid a dowry or recognized a rent of 15,000 livres due to Charles. John further irritated Charles by giving the new constable of France, Charles de La Cerda, lands that were claimed by Charles of Navarre. In revenge, the latter had the new constable assassinated; but in spite of John's rage, the two kings made a superficial peace in February 1354. Charles desired an alliance with Edward, which so frightened John that he made another peace with Charles on Sept. 10, 1355. On April 16, 1356, at Rouen, John took his revenge on Charles by having him imprisoned.

Meanwhile Edward, displeased by the 1355 alliance between John and Charles, invaded France later that year but then returned to England before any confrontations. At the same time, Edward's son Edward (Edward The Black Prince), prince of Wales (later called the Black Prince), attacked southern France. Unable to halt the English invasions because he lacked funds, John gathered the States General to seek money and to impose an unpopular salt tax. John first went to defend Paris and Chartres. He and the Prince of Wales finally met near Poitiers in September 1356. The French army was decimated, and John was taken prisoner.

John was taken to London in April 1357, where he was lodged in the Savoy palace; there he concluded treaties (January 1358 and March 1359) so harsh that they were repudiated in France. Finally the treaties of Brétigny and of Calais (May and October 1360) fixed John's ransom at 3,000,000 gold écus and surrendered most of southwestern France to Edward. On Oct. 9, 1360, John was released to raise a ransom that France could not afford to pay, and hostages were accepted in his place. When one of the hostages (John's own son) escaped, John, feeling dishonoured, returned to England on his own volition as a prisoner.

John was the great-grandson of the founder of the House of Aviz, John I, and only surviving son of Afonso V by his queen and cousin, Isabella. He was educated by the humanists of the court and was married to his cousin Leonor in 1471. He participated in his father's conquest of Arzila in Morocco, where he was knighted, and was given a separate household at Beja in southern Portugal. In 1474 his father entrusted him with the “trade of Guinea” and the African explorations. When Afonso V claimed the Castilian throne in opposition to Isabella I, plunging Portugal into war, he appointed John his regent (April 1475). The Prince mobilized an army and marched to support his father, but the Battle of Toro (March 1476) checked the Portuguese intrusion into Castile. Afonso V departed for France in a fruitless search for an alliance, while John defended the frontier and parried a Spanish counterattack. Afonso's lack of success caused him to announce his abdication. John was proclaimed king, but his father returned and resumed his reign, concluding the disadvantageous Treaty of Alcáçovas before his death in August 1481.

At John II's accession, this peace treaty had obliged him to place his young children under Spanish guardianship near the frontier as a pledge of their marriage to Castilians. Afonso had been limited in authority by the ambitious House of Bragança (Bragança, House of), the wealthiest family in Portugal. John summoned the Cortes (assembly) at Évora (November 1481) and imposed a drastic oath of obedience on his vassals. He also reasserted the beneplacet, requiring papal letters to be submitted to him before publication. He successfully negotiated a revision of the treaty with Spain, by which his children were restored to him. He then accused the Duke of Bragança of treason and had him tried and beheaded at Évora (June 1483). Although evidence was produced that the Braganças had intrigued with Castile, it seems clear that John sought vengeance for their having caused the death of his maternal grandfather, the regent Dom Pedro. He confiscated the Braganças' vast estates and appointed royal judges in what had been private jurisdictions of the nobility. When a second conspiracy sought to remove him and bestow the crown on his wife's brother the Duke of Viseu, John killed his rival with his own hand (August 1484).

In Africa Afonso V had preferred crusading in Morocco to trade and discovery of the west coast. John II himself never returned to Africa after Arzila but supported the development of commerce and exploration.

In December 1481 he sent Diogo de Azambuja to build the fortress of St. George at Mina (the “gold mine”), near Benin, a powerful native kingdom in the territory of modern Nigeria. Gold currency had been restored by his father, and the new trade now doubled the royal revenues, and in 1485 John assumed the title of lord of Guinea. He had already sent Diogo Cão to search for the seaway to India, and Cão had discovered the mouth of the Congo River. Christopher Columbus tried to interest him in his plan to reach India by a western route. John rejected this but licensed Fernão Dulmo to search for new islands, apparently without result. In 1485 he sent Cão on a second voyage that reached southwestern Africa but failed to find the Cape. When in 1486 merchants in Benin heard news of a native potentate far to the east who was thought to be the legendary Christian ruler Prester John, the King sent Pero da Covilhã and Afonso Paiva to visit India and Ethiopia by an overland route. He also sent Bartolomeu Dias to take over Cão's task of finding the southern extremity of Africa; Dias' return in December 1488 demonstrated that Africa could be rounded and India reached by sea, but it was only after John's death that Vasco da Gama's successful expedition to India was launched. In 1490 a mission was sent to consolidate relations with the Kongo kingdom. In 1493 Columbus arrived in Lisbon with tidings of, as he supposed, islands off Asia, and the Pope awarded these discoveries to the Spanish crown. But John II protested and began negotiations leading to the celebrated Treaty of Tordesillas (Tordesillas, Treaty of) (June 1494), which gave to Spain all lands west of a line 370 leagues to the west of the Cape Verde Islands. This line, however, reserved Brazil (still apparently unknown) for Portugal.

John had previously negotiated with the papacy, ceding the beneplacet but retaining the right to have ecclesiastical cases settled in Portugal and obtaining permission for a crusade against the Moors. He sent a minor expedition against Anafé and obtained tribute from Safi and Azemmour in Morocco, but in 1489 his attempt to build a fortress at the mouth of the Loukkos was prevented by the ruler of Fez.

When in May 1492 Ferdinand and Isabella of Spain decided to expel the Jewish population, John received a delegation of Spanish Jews (Jew) who offered 60,000 cruzados for the permanent admission of 600 wealthy families to Portugal, together with a fee of eight cruzados a head for the temporary admission of others, who would be allowed to remain eight months, after which John would supply ships for them to leave. In fact, ships were provided only for Tangier and Arzila; some Jewish children were sent to settle the island of São Tomé.

John's son Afonso was married to the eldest daughter of the Spanish rulers, but soon thereafter the Prince was thrown from a horse and killed (July 1491). John was deeply affected. He thought of legitimizing his other son Jorge but had already promised the succession to his wife's surviving brother, Manuel. He suffered a long illness and died in 1495 at the small castle of Alvor in the province of Algarve. John's exercise of personal power, particularly against the nobles, explains the epithet the Perfect Prince, which owes its origin to Lope de Vega's play about him.

pope from 533 to 535. He was the first pontiff to change his original name, which he considered pagan, assuming the name of the martyred St. John (523–526).

John's pontificate opposed Nestorianism (Nestorian), the heresy that separated the divine and human natures of Christ and denied the Virgin Mary the title Mother of God. Nestorianism had been condemned by the Council of Chalcedon in 451. In 534 the Byzantine emperor Justinian I persuaded John to condemn the Acoemeti, a group of monks in Constantinople who had adopted Nestorianism. They were excommunicated on March 24/25, 534, thus ending the Theopaschite controversy.