FERDINAND III. (1608-1657), Roman emperor, was the elder son of the emperor Ferdinand II., and was born at Gratz on July 13, 1608. Educated by the Jesuits, he was crowned king of Hungary in December 1625, and king of Bohemia two years later, and soon began to take part in imperial business. Wallen stein, however, refused to allow him to hold a command in the imperial army. The young king was appointed the successor of the famous general when he was deposed in 1634; and as com mander-in-chief of the imperial troops, he was nominally re sponsible for the capture of Regensburg and Donauworth, and the defeat of the Swedes at Nordlingen. Having been elected king of the Romans, or German king, at Regensburg in Dec. 1636, Ferdinand became emperor on his father's death in the following February, and showed himself anxious to put an end to the Thirty Years' War. But he was reluctant to grant religious liberty to the Protestants, and anxious to act in unison with Spain. In 1640 he had refused to entertain the idea of a general amnesty sug gested by the diet at Regensburg ; but in 1648 he assented to the treaty of Westphalia (q.v.). Owing to Ferdinand's insistence the Protestants in his hereditary dominions did not obtain reli gious liberty at this settlement. After 1648 the emperor was en gaged in carrying out the terms of the treaty and ridding Germany of the foreign soldiery. In 1656 he sent an army into Italy to assist Spain in her struggle with France, and he had just con cluded an alliance with Poland to check the aggressions of Charles X. of Sweden when he died on April 2, 1657. Ferdinand was a scholarly and cultured man, an excellent linguist and a composer of music. His first wife was Maria Anna (d. 1646), daughter of Philip III. of Spain, by whom he had three sons : Ferdinand, who was chosen king of the Romans in 1653, and who died in the following year; Leopold, who succeeded his father on the im perial throne; and Charles Joseph (d. 1664), bishop of Passau and Breslau, and grand-master of the Teutonic order. The emperor's second wife was his cousin Maria (d. 1649), daughter of the archduke Leopold; and his third wife was Eleanora of Mantua (d. 1686). His musical works, together with those of the em perors Leopold I. and Joseph I., have been published by G. Adler (Vienna, 1892-1893).
See M. Koch, Geschichte des deutschen Reiches unter der Regierung Ferdinands III. (Vienna, 2 vols., x865-66).