Leopold, the second son of Ferdinand III's first marriage, to his cousin Maria Anna, daughter of Philip III of Spain, was destined for the church. He received a careful education by excellent teachers, among whom the cultured count Johann Ferdinand Portia was the leading personality. Made lord high steward by his pupil, Portia retained his influence with Leopold until his death in 1665. From an early age Leopold showed an inclination toward learning. He learned easily and became fluent in Latin, Italian, and Spanish, but he did not like French and later would not have it spoken at court. Besides concerning himself with antiquarian studies, history, literature, natural science, and astronomy, his special interest was music, having inherited the musical talents of his father. The keynote of his personality was a deep devotion, which made him the personification of pietas Austriaca, the loyal Catholic attitude of his house. From his religiosity, however, also derived a fatalistic strain, which had its negative side for a ruling monarch. He rejected all political compromising on denominational questions.

When his elder brother, Ferdinand IV, died quite unexpectedly (July 9, 1654), Leopold suddenly found himself heir apparent to the Austrian Habsburg lands. In 1655 the Lower Austrian estates did homage, and he was elected and crowned king of Hungary, the Bohemian coronation following in 1656. Then, in 1657, his father died, and a new imperial election was due. After long and difficult struggles against the opposition of France, Leopold was elected and crowned in the summer of 1658.

Leopold acquired a claim to the Spanish throne by his first marriage, in 1666, to Margarita Teresa, daughter of Philip IV of Spain; she died in 1673. Leopold's health was bad, and, when he fell dangerously ill in 1670, everybody expected the Austrian line of the Habsburgs to become extinct. He recovered, however, and in 1673 married Claudia Felicitas from the Tirolian branch of the Austrian Habsburgs. In 1676 the Emperor solemnized his third marriage, with Eleonore of Palatinate–Neuburg; this proved a happy union and produced 10 children, among them the future emperors Joseph I and Charles VI.

With untiring energy and a deep sense of duty, Leopold undertook the unwonted task of government. From the beginning he had to fight wars, first of all against the Turks (Ottoman Empire). In 1683 they appeared before Vienna (Vienna, Siege of), and for the second time in its history the city suffered a Turkish siege. Leopold had left the capital with his court to await the outcome at Passau. An imperial army was summoned, and from the time of their repulse at Vienna the Turks were gradually forced into the defensive, especially after the military genius of Prince Eugene of Savoy appeared on the scene in 1696. In the Treaty of Carlowitz (Carlowitz, Treaty of) (1699), almost the whole of Hungary was freed from Turkish rule.

The Hungarian nobles, however, who were mostly Calvinists, did not want to exchange Turkish rule for a centralized Habsburg government, which threatened to introduce the Counter-Reformation. Their opposition had been a serious problem all the time, and Leopold, who usually showed clemency, took a firm stand for once, refusing to recall the cruel sentences after the so-called Nobles' Plot. Three of the most prominent Hungarian noblemen were executed, and Hungarian resistance flared up again in the fierce Kuruc risings.

Though Leopold's policy toward Catholic France (Louis XIV) was undecided at first, he finally had to agree to a coalition with the Protestant naval powers, Holland and England. In the course of the long struggle (Grand Alliance, War of the) with France, the empire scored several military successes; but in the end French diplomacy remained victorious, always dividing the enemy at the decisive moment. The Emperor was accused of a wavering attitude and lack of initiative, and these character traits were indeed partly responsible for the failure of his policies. The war ended in the unfavourable Treaty of Rijswijk (1697), under the terms of which Strasbourg had to be ceded to France, a great discredit to Leopold.

Apart from some contributions from the empire and subsidies from its allies, the financial burden of all these wars had to be borne by Leopold's hereditary countries, the finances of which were badly organized. During his long reign Leopold found it impossible to arrive at a sound financial basis; indeed, he was careless in these matters and for years suffered the treasury to be mismanaged by Count Sinzendorf.

Emperor Leopold was not always fortunate in the choice of his ministers. There was, for example, Count Eusebius Pötting, with whom he had formed a warm friendship but who was not the right man for the post of ambassador to Madrid. On the other hand, councillors who had convinced the Emperor of their sincerity and honesty found excellent chances for a court career, even if they were middle class, like the Austrian court chancellor Johann Paul Hocher.

Leopold no longer regarded the empire as his primary responsibility; rather, in his view, concern for the power and prestige of the Habsburg dynasty and lands took the first place. From the outset the Spanish succession (Spanish Succession, War of the) formed the central aim of his politics. What lay behind this was the idea of the unity of the House of Habsburg, the two lines being considered only as parts of the same entail. At the death (1700) of the childless Charles II of Spain, his throne and the vast Spanish holdings passed by bequest to Philippe, duc d'Anjou, a grandson of Louis XIV of France. There could be no question for Emperor Leopold that the Spanish heritage had to be defended by force of arms. In the middle of the War of the Spanish Succession (Spanish Succession, War of the) (q.v.; 1701–14), Leopold died. He was buried in the Habsburg mausoleum of the Capuchins at Vienna.

The Emperor was of medium size, rather slender in his youth but stout in later life. His face was pale, and he had dark hair and the typical Habsburg traits of a strongly developed lower lip and a protruding chin. A Turkish traveller described him as a cultivated man of extreme ugliness.

If the Emperor, who had not been trained for the throne, rarely interfered with the course of events, he, nevertheless, impressed contemporaries with an imperturbability founded in personal piety, which did not fail him even during the worst crises to his long reign. His biographer, the Jesuit Hans Jacob Wagner von Wagenfels (died 1702), quite aptly praises his magnanimity as his most conspicuous character trait. The interest Leopold took in all matters of learning, his gift for music, and his preoccupation with historiography made him a patron of renown and, notwithstanding the military conflicts of the time and his precarious finances, gave enormous impetus to learning and the arts throughout the Austrian countries and especially made Vienna a famous cultural centre. His reign saw the first flourishing of Baroque culture in Austria.

In spite of the Emperor's great personal simplicity, the sums expended to maintain the imperial court were gigantic. At all occasions the Emperor was anxious to emphasize his imperial dignity; official journeys, such as his coronation journey to Frankfurt in 1658, as well as the numerous pilgrimages he undertook to assure divine assistance against his enemies, were used for ostentation. A special concern of the Emperor was to reshape Vienna into a worthy imperial residence. The Vienna court was famous for its costly theatricals, in which at times the Emperor and Empress also took part. Italian operas and ballets were lavishly staged, often with some additional music composed by Leopold himself. As the Emperor was very fond of hunting, courtly pleasures also included heron hawking and hunting wild boars and stags in the vicinity of the residence. Though Leopold undertook no more extensive journeys after 1693, he enjoyed these regular hunting expeditions until his death.

Leopold I was a devoted book collector and, in the director of the court library, Peter Lambeck, found a helper of great renown. He was known for the encouragement he extended to learning, whereby he tried to secure the services of famous scholars for his court.

first king of the Belgians (1831–65), who helped strengthen the nation's new parliamentary system and, as a leading figure in European diplomacy, scrupulously maintained Belgian neutrality.

The fourth son of Francis, duke of Saxe-Coburg-Saalfeld, Leopold served with the allies against Napoleon's forces during the Napoleonic Wars (1800–15); in 1816 he married Charlotte, the only child of the future king George IV of Great Britain. Although the Princess died in 1817, Leopold continued to live in England until 1831, when he accepted his election as king of the Belgians, having declined the Greek crown the previous year. He immediately began to strengthen the Belgian Army and, with assistance from France and England, fought off the attacks of William I of The Netherlands, who refused until 1839 to recognize Belgium as an independent kingdom.

Until 1839 Leopold helped maintain a Liberal–Catholic coalition that expanded the educational system. In 1836 he granted greater political autonomy to large towns and rural areas. The coalition ended in 1839 with the removal of Dutch pressure through William I's recognition of the Belgian kingdom. Leopold signed commercial treaties with Prussia (1844) and France (1846) and maintained a neutral foreign policy, most notably during the Crimean War (1853–56). His throne was not seriously challenged during the revolutions of 1848. After the accession of a hostile regime under Napoleon III in France (1852), he sponsored a fortification of the Antwerp area, completed in 1868.

Often referred to as the “Nestor of Europe,” Leopold was highly influential in European diplomacy and used marriages to strengthen his ties with France, England, and Austria. He married Marie-Louise of Orléans, daughter of the French king Louis-Philippe, in 1832; in 1840 he helped to arrange the marriage of his niece Victoria, queen of England, to his nephew Prince Albert of Saxe-Coburg-Gotha (Albert, Prince Consort of Great Britain and Ireland). He also helped negotiate the marriage of his daughter Carlota to Maximilian, archduke of Austria and later emperor of Mexico, in 1857. Leopold's influence declined with the growing power of Napoleon III and of Otto von Bismarck of Prussia.

Beginning his military career serving against the French in 1695, Leopold commanded the Prussian contingent in the allied forces during most of the War of the Spanish Succession (1701–14). A friend of the Austrian field marshal Prince Eugene of Savoy, he fought in Germany, Italy, the Netherlands, and France, distinguishing himself at the battles of Höchstädt an der Donau (Bavaria; 1703), Cassano d'Adda (Italy; 1705), Turin (1706), Tournai (Belgium), and Malplaquet (France; both 1709). In 1715 he commanded the Prussian Army against Charles XII of Sweden, defeating him at Stralsund and on the island of Rügen.

The long peace that followed gave Leopold the chance to use his considerable organizational talents. Introducing the iron ramrod (wooden ones tended to break in the heat of battle), the modern bayonet (replacing the plug bayonet that had to be removed from the barrel to fire the weapon), and the uniform marching step in his own regiment in the late 1690s, he extended these improvements to the entire Prussian Army after 1715. Under his strict, often brutal tutelage, the Prussian infantry achieved the discipline and rapidity of fire that made possible Frederick II's victories against vastly more numerous and powerful foes. In this endeavour, Leopold had the confidence and cooperation of his monarch, King Frederick William I (ruled 1713–40). As a result of his experience in the field, the Prince always favoured his own branch of the service, infantry, over cavalry and artillery.

After the succession of Frederick II in 1740, war again broke out. Leopold, by now an old man, once more took a field command. On Dec. 14, 1745, as Frederick was hurrying to his aid, the “Old Dessauer” defeated a superior Austrian and Saxon army at Kesselsdorf, Saxony, the final action of his long career.