Ferdinand I. had married the sister of Lewis II. of Hungary; and on the death of the latter in the battle of Mohacz (1526), he claimed the kingdoms of Hungary and Bohemia, along with Moravia, Silesia, and Lausatia. His claim was contested by John Zapolya, who secured the aid of sultan Soliman II.; and Ferdinand, after contests extending over 20 years, had finally to pay an annual tribute of 30,000 ducats to Soli man for possession of Lower Hungary. Ferdinand was also fain to surrender Wiirtemberg to Duke Ulrich (1534), on condition of its reverting to A. on the death of the male line. Nevertheless, the possessions of the house of A. (in the German line) were at this time already of the extent of 110,000 sq. miles. On the abdication of Charles V. (1556), Fer dinand succeeded to the imperial dignity; he died 1564, with the reputation of a good ruler, though he was strongly conservative of everything established, and introduced the Jesuits.
In the partition of the inheritance that took place among his three sons, the eldest, Maximilian II., received the imperial crown along with A., Hungary, and Bohemia; the second, Ferdinand, Tyrol and Upper A.; the third, Karl, Styria, Carinthia, etc. Maximilian was more fortnnate in Hungary than his father. The death of Soliman before Szigeth (1566) led to a truce; he got his eldest son, Rudolf, crowned king of Hun gary in 1572, and shortly after, of Bohemia, and also chosen king of Rome. But his attempt to bring the crown of Poland into his house failed. .Maximilian II. was fond of peace, tolerant in religion, and a just ruler. He died 1576; and of his 5 sons, the eldest, Rudolf II., became emperor. Under him, the possessions of the archduke Ferdinand of Tyrol, who had married Philippine Weiser (q.v.), the beautiful daughter of an Augs burg burgher, reverted to the other two lines, Ferdinand's children not being considered noble. Rudolf II, adhered to the old feudal usages. and was a negligent sovereign, leaving everything to his ministers and the Jesuits. His war with the porte and Tran sylvania brought him little credit; and the Protestants of Bohemia, oppressed by the J'esuits, extorted from him a charter of religious liberty. At last he was obliged. in 1608, to cede Hungary, and, in 1611, Bohemia and A. to his brother Matthias (q.v.). Matthias, who became emperor in 1612, conchided a 20 years' peace with the Turks, and ceded (1617 and 1618) Bohemia and Hungary to his cousin Ferdinand, of the archduke Karl of Styria, third son of Maximilian II. Matthias lived to see the outbreak of the thirty years' war (q.v.), and died March 20, 1619.
Bohemia refused to acknowledge his successor, Ferdinand II. (q.v.), to whom all the Austrian possessions had again reverted, and chose the elector palatine, Frederic V., the head of the Protestant union, as king. The states of A. and the Hungarians were also refractory. But the battle of Prague (1620) subjected Bohemia to Ferdinand; who formally set about rooting out Protestantism in that country and in Moravia, annulled their right of electing their king, and the patent of religious freedom granted them by Rudolf II., and set up a Catholic reformation tribunal which drove thousands into exile.
The emperor also succeeded in extorting acknowledgment of his sovereignty from the states of A., among which Protestantism predominated; after which Protestantism was rigorously prohibited. Hungary also was at last compelled to yield, which had revolted under the prince of Transylvania. But this religious war and persecution cost the house of A. the life-blood of its possessions. Of 732 cities in Bohemia, only 130 were left; of 30,700 villages, only 6000; of 3,000,000 inhabitants, only 780,000. Under Ferdinand's successor, the emperor Ferdinand III. (1637-1657), A. continued to be a theater of war; and at the peace of Westphalia (1648), had to cede Alsace to France. Ferdinand M.'s son and successor, Leopold I., provoked the Hungarians to rebellion by his sever ity. Tekeli (q.v.) received aid from the porte, and Kara Mustapha besieged Vienna (1083); which was rescued only by an army of Poles and Germans under John Sobieski hastening to its assistance. The emperor's generals now reduced the whole of Hungary, which was declared a hereditary kingdom in the male line (1687). Prince Eugene com pelled the porte (1699) to restore the country between the Danube and Theiss, and, in 1718, to cede other important provinces to The struggle between Leopold and Louis XIV. of France for the heirship to the king of Spain, led to the war of the Spanish succession (q.v.), during which Leopold died, May 5, 1705. He was of sluggish Meg-made character, and wholly under the influence of the Jesuits.
His eldest son and successor, the enlightened Joseph I. (q.v.), continued the war. He d. childless, April 17, 1711, and was succeeded by his brother, Karl VI. The peace of Utrecht concluded under his reign (1713) secured to A. the Netherlands, Milan, Mantua, Naples, and Sicily. The monarchy now embraced 190,000 sq.m., with 29,000,000 inhab itants, and had a revenue of 14, 000,000 florins, with an army of 130,000 men. Its strength, however, was soon much exhausted by fresh wars with France and Spain. At the peace of Vienna (1737), Karl VI. had to give up Naples and Sicily to Don Carlos of Spain, and part of Milan to the king of Sardinia. receiving only Parma and Piacenza instead. He also lost at the peace of Belgrade (1739) nearly all the fruits of Eugene's conquests, giving back to the porte Belgrade, Servia, and the parts of Wallachia. and Bosnia that had belonged to Austria. The emperor conceded all these points with the view of securing adhesion to the pragmatic sanction (q.v.), which conferred the succes sion on his daughter, Maria Theresa.