Sigismund (1368-1437), Roman emperor and king of Hungary and Bohemia, was a son of the emperor Charles IV. and Elizabeth, daughter of Bogislaus V., duke of Pomerania. He was born on the 15th of February 1368, and in 1374 was betrothed to Maria, the eldest daughter of Louis the Great, king of Poland and Hungary. Having become margrave of Brandenburg on his father's death in 1378, he was educated at the Hungarian court from his eleventh to his sixteenth year, becoming thoroughly magyarized and entirely devoted to his adopted country. His wife Maria, to whom he was married in 1385, was captured by the rebellious Horvathys in the following year, and only rescued by her young husband with the aid of the Venetians in June 1387. Sigismund had been crowned king of Hungary on the 31st of March 1387, and having raised money by pledging Brandenburg to his cousin Jobst, margrave of Moravia, he was engaged for the next nine years in a ceaseless struggle for the possession of this unstable throne. The bulk of the nation headed by the great Garay family was with him; but in the southern provinces between the Save and the Drave, the Horvathys with the support of the Bosnian king Tvrtko, proclaimed as their king Ladislaus, king of Naples, son of the murdered Hungarian king, Charles II. (see Hungary). Not until 1395 did the valiant Miklos Garay succeed in suppressing them. In 1396 Sigismund led the combined armies of Christendom against the Turks, who had taken advantage of the temporary helplessness of Hungary to extend their dominion to the banks of the Danube. This crusade, preached by Pope Boniface IX., was very popular in Hungary. The nobles flocked in thousands to the royal standard, and were reinforced by volunteers from nearly every part of Europe, the most important contingent being that of the French led by John, duke of Nevers, son of Philip II., duke of Burgundy. It was with a host of about 90,000 men and a flotilla of 70 galleys that Sigismund set out. After capturing Widdin, he sat down before the fortress of Nicopolis, to retain which Sultan Bajazid raised the siege of Constantinople and at the head of 140,000 men completely overthrew the Christian forces in a battle fought between the 25th and 28th of September 1396. Deprived of his authority in Hungary, Sigismund then turned his attention to securing the succession in Germany and Bohemia, and was recognized by his childless step-brother Wenceslaus as vicar-general of the whole empire. He remained, however, powerless when in 1400 Wenceslaus was deposed and Rupert III., elector palatine of the Rhine, was elected German king in his stead. During these years he was also involved in domestic difficulties out of which sprang a second war with Ladislaus of Naples; and on his return to Hungary in 1401 he was once imprisoned and twice deposed. This struggle in its turn led to a war with Venice, as Ladislaus before departing to his own land had sold the Dalmatian cities to the Venetians for 100,000 ducats. In 1401 Sigismund assisted a rising against Wenceslaus, during the course of which the German and Bohemian king was made a prisoner, and Sigismund ruled Bohemia for nineteen months. In 1410 the German king Rupert died, when Sigismund, ignoring his step-brother's title, was chosen German king, or king of the Romans, first by three of the electors on the 10th of September 1410, and again after the death of his rival, Jobst of Moravia, on the 21st of July 1411; but his coronation was deferred until the 8th of November 1414, when it took place at Aix-la-Chapelle.
During a visit to Italy the king had taken advantage of the difficulties of Pope John XXIII. to obtain a promise that a council should be called to Constance in 1414. He took a leading part in the deliberations of this assembly, and during the sittings made a journey into France, England and Burgundy in a vain attempt to secure the abdication of the three rival popes (see Constance, Council Of). The complicity of Sigismund in the death of John Huss is a matter of controversy. He had granted him a safe-conduct and protested against his imprisonment; and it was during his absence that the reformer was burned. An alliance with England against France, and an attempt to secure peace in Germany by a league of the towns, which failed owing to the hostility of the princes, were the main secular proceedings of these years. In 1419 the death of Wenceslaus left Sigismund titular king of Bohemia, but he had to wait for seventeen years before the Czechs would acknowledge him. But although the two dignities of king of the Romans and king of Bohemia added considerably to his importance, and indeed made him the nominal head of Christendom, they conferred no increase of power and financially embarrassed him. It was only as king of Hungary that he had succeeded in establishing his authority and in doing anything for the order and good government of the land. Entrusting the government of Bohemia to Sophia, the widow of Wenceslaus, he hastened into Hungary; but the Bohemians, who distrusted him as the betrayer of Huss, were soon in arms; and the flame was fanned when Sigismund declared his intention of prosecuting the war against heretics who were also communists. Three campaigns against the Hussites ended in disaster; the Turks were again attacking Hungary; and the king, unable to obtain support from the German princes, was powerless in Bohemia. His attempts at the diet of Nuremberg in 1422 to raise a mercenary army were foiled by the resistance of the towns; and in 1424 the electors, among whom was Sigismund's former ally, Frederick I. of Hohenzollern, margrave of Brandenburg, sought to strengthen their own authority at the expense of the king. Although the scheme failed, the danger to Germany from the Hussites led to fresh proposals, the result of which was that Sigismund was virtually deprived of the leadership of the war and the headship of Germany. In 1431 he went to Milan where on the 25th of November he received the Lombard crown; after which he remained for some time at Siena, negotiating for his coronation as emperor and for the recognition of the Council of Basel by Pope Eugenius IV. He was crowned emperor at Rome on the 31st of May 1433, and after obtaining his demands from the pope returned to Bohemia, where he was recognized as king in 1436, though his power was little more than nominal. On the 9th of December 1437 he died at Znaim, and was buried at Grosswardein. By his second wife, Barbara of Cilli, he left an only daughter, Elizabeth, who was married to Albert V., duke of Austria, afterwards the German king Albert II., whom he named as his successor. As he left no sons the house of Luxemburg became extinct on his death.
Sigismund was brave and handsome, courtly in his bearing, eloquent in his speech, but licentious in his manners. He was an accomplished knight and is said to have known seven languages. He was also one of the most far-seeing statesmen of his day, and steadily endeavoured to bring about the expulsion of the Turks from Europe by uniting Christendom against them. As king of Hungary he approved himself a born political reformer, and the military measures which he adopted in that country enabled the kingdom to hold its own against the Turks for nearly a hundred years. His sense of justice and honour was slight; but as regards the death of Huss he had to choose between condoning the act and allowing the council to break up without result. He cannot be entirely blamed for the misfortunes of Germany during his reign, for he showed a willingness to attempt reform; but he was easily discouraged, and was hampered on all sides by poverty, which often compelled him to resort to the meanest expedients for raising money.
Bibliography. - The more important works to be consulted are Repertorium Germanicum; Regesten aus den peipstlichen Archiven zur Geschichte des deutschen Reichs im XI V. and X V. Jahrhundert (Berlin, 1897); E. Windecke, Denkwurdigkeiten zur Geschichte des Zeitalters Kaisers Sigmund (Berlin, 1893), and Das Leben Konigs Siegmund (Berlin, 1886); J. Aschbach, Geschichte Kaiser Sigmunds (Hamburg, 1838-1845); W. Berger, Johannes Hus and Konig Sigmund (Augsburg, 1871); G. Schonherr, The Inheritors of the House of Anjou (Buda-Pesth, 1895); and J. Acsa.dy, History of the Hungarian Realm, vol. i. (Buda-Pesth, 1903). Of the German books Aschbach is the fullest, and Windecke the most critical. Schonherr is the best "HHungarian authority. Acsady is too indulgent to the vices of Sigismund. See also A. Main, The Emperor Sigismund (1903).