FREDERICK IV. (1415-1493), German king, as em-peror Frederick III., son of Duke Ernest of Styria, was born at Innsbruck, September 21, 1415. Along with his brother Albert the Prodigal he assumed in 1435 the govern-ment of Styria, Carinthia, and Carniola, and, having been elected in 1440 to succeed Albert II. as king of Germany, he was crowned at Aix-la-Chapelle in 1442. He devoted his chief attention to the study of astrology, alchemy, and botany, and was so undecided in his purposes and so de-ficient in energy and force of character that he almost pas-sively submitted to the anarchy and petty external wars which during the whole of his reign disturbed the peace of the empire. At the beginning of his reign he was attacked by his brother Albert, who reigned in Upper Austria, and he found it necessary to pacify him by the payment of a large sum of money; in 1443 he was attacked by the Swiss, and called to his aid the Armagnacs from France, who, how-ever, after their defeat by the Swiss at St Jakob in 1444, joined his enemies against him, and in 1449 he was com-pelled to agree to an unfavourable treaty; from 1445 to 1452 Austria was invaded by the Hungarians ; in 1447 Sforza successfully usurped the government of Milan; from 1449 to 1456 a war was carried on between Albert of Branden-burg and the city of Nuremberg assisted by the "Eidge-nossen;" and from 1449 to 1462 a succession war raged in the Rhenish Palatinate, Frederick, who hoped by cul-tivating the friendship of the Papacy to win back some of the ancient imperial rights, concluded in 1448 the con-cordat of Vienna with Pope Nicholas V., and was crowned emperor in 1452. On the death of Ladislaus duke of Austria in 1457, he laid claim to the whole of Austria, and also to the crown of Bohemia and Hungary; but not only was George Podiebrad made king of Bohemia and Matthias Corvinus king of Hungary, but Sigismund of Tyrol obtained part of Carinthia, and Frederick's brother Albert, besides seizing Upper Austria in 1462, took posses-sion of Vienna. On the death of Albert in 1463, Frederick obtained possession of the whole of Austria, with the exception of Carinthia. Notwithstanding that Frederick in 1468 went to Bome to concert measures with the pope against the Turks, they in 1469 penetrated without resist-ance to Carniola, and in 1475 advanced nearly to Salzburg, In 1473 he suddenly broke off a negotiation with Charles the Bold at Treves for the marriage of Charles's daughter with his son Maximilian, but the marriage finally took place after the death of Charles, and Maximilian thus be-came king of the Netherlands. The changeful and crooked policy of the emperor in reference to Poland and Hungary led the kings of both countries to turn their arms against him, and in 1485 Matthias of Hungary drove him from his hereditary dominions, of which he did not regain possession till after the death of Matthias in 1490. Frederick died in 1493.

See Chmel, Regcsta Friderici IV., Vienna, 1838-40; Kurz, Oesterreich unter Kaiser Friedrich IV., Vienna, 1812; Chmel, Geschichte Kaiser Friedrichs IV., Hamburg, 1840; Archiv für Oesterr. Geschichtsquellen, vols. x. and xi.; Müller, Reichstagsstaat unter Friedrich III., 3 vols.