King of Hungary from 1387, leader of the disastrous Nicopolis crusade of 1396, convener of the Council of Constance, and finally Holy Roman Emperor — the last ruler of the House of Luxembourg.
Sigismund of Luxembourg spent fifty years holding together more crowns than any ruler of his age: king of Hungary from 1387, king of the Romans from 1411, king of Bohemia from 1419, and Holy Roman Emperor from 1433. Son of the emperor Charles IV, he won Hungary through marriage to Queen Mary and defended it for the rest of his life against the advancing Ottoman Empire.
That defence produced the catastrophe that marked him: the great crusade he assembled in 1396, the largest of the late Middle Ages, was annihilated by Bayezid I at the Battle of Nicopolis, and Sigismund escaped down the Danube in a fishing boat. His later fame rests on diplomacy rather than arms — above all the Council of Constance (1414–1418), which he forced into being and which ended the Great Schism of the papacy, though at the cost of Jan Hus's burning and the Hussite wars that scarred his Bohemian inheritance.
Sigismund was born in Nuremberg on 15 February 1368, a younger son of the emperor Charles IV, the Luxembourg ruler who had made Prague the capital of the Empire and issued the Golden Bull of 1356. Betrothed as a child to Mary, heiress of Louis the Great of Hungary and Poland, he was raised partly at the Hungarian court for that inheritance. Winning it proved brutal: after Louis died in 1382 Mary's succession collapsed into civil war, her rival Charles of Durazzo was murdered, and Mary and her mother were imprisoned by rebel barons. Sigismund fought his way to the crown of Hungary, being crowned at Székesfehérvár in March 1387, and ruled first alongside Mary and, after her death in 1395, alone.
Contemporaries found Sigismund magnificent, charming, and impossible to pin down. Tall, striking, fluent in several languages, he dazzled the courts of Europe on the great diplomatic circuits of 1414–1417 that carried him to Paris, London, and Aragon in pursuit of church union; even hostile observers conceded his energy and his gift for the grand occasion. The Constance chroniclers show a ruler who genuinely drove the council — bullying, mediating, and stage-managing until the schism of three rival popes was ended.
The debts of the style were as visible as its triumphs. He was chronically short of money, pawning towns and offices — including the Brandenburg electorate his father had gathered — to fund his projects; his promises could be flexible, and the safe conduct he issued to Jan Hus, who was burned at Constance in 1415 regardless, left a permanent stain that Czech tradition never forgave. Hungarian and German chroniclers alike noted the gap between his imperial vision and his patience for administration; modern historians tend to see a ruler of real strategic intelligence — the Ottoman danger, the church crisis, and the Hussite problem were all correctly judged — whose resources never matched the scale of his ambitions.
Hungary under Sigismund stood on the front line of Ottoman expansion into the Balkans, and after Bayezid I's armies pressed to the Danube he appealed to all Christendom. The response of 1396 was the last great international crusade: French and Burgundian chivalry under John the Fearless, then count of Nevers, joined Sigismund's Hungarians, with German, Wallachian, and Hospitaller contingents, and marched down the Danube to besiege the fortress of Nicopolis. On 25 September 1396 Bayezid's relieving army destroyed them at the Battle of Nicopolis; the French knights charged uphill against Sigismund's advice, broke themselves on the Ottoman lines, and the counterattack swept the field. Sigismund escaped by boat down the Danube and returned home by sea through Constantinople.
The defeat fixed the pattern of his southern policy for forty years: no more grand crusades, but a defensive system of border fortresses, client princes in Serbia, Bosnia, and Wallachia, and the militia and banderial reforms of 1397 and after that reorganised Hungary's defence. It bought time rather than victory, but the Danube line he organised — anchored on Belgrade after 1427 — held the Ottoman advance at bay for a generation beyond his death, until the wars of John Hunyadi.
Elected king of the Romans in 1411, Sigismund made the healing of the Great Schism his imperial mission. He compelled the Pisan pope John XXIII to summon a general council to Constance in 1414, and for four years acted as its protector and chief political engine: the council deposed or accepted the resignation of the three rival popes and elected Martin V in 1417, restoring a single head to the Latin Church for the first time in nearly forty years. It was the greatest diplomatic achievement of the age — and it was bought with the burning of the Czech reformer Jan Hus in 1415, who had come to Constance under Sigismund's safe conduct.
Bohemia never forgave it. When his childless brother Wenceslas IV died in 1419, Sigismund inherited the Bohemian crown just as the Hussite revolution exploded; his crusades against the Hussites in the 1420s were repeatedly routed by Jan Žižka's war-wagon armies, and only the negotiated Compacts of Basel allowed him to be accepted in Prague in 1436, a year before his death. The imperial crown itself came late: he was crowned Holy Roman Emperor in Rome by Pope Eugenius IV on 31 May 1433, the first emperor crowned there in over eighty years.
Sigismund died at Znojmo in Moravia on 9 December 1437, aged sixty-nine, while withdrawing from a Bohemia again slipping toward revolt. He had arranged the succession of his son-in-law Albert of Habsburg — husband of his daughter Elizabeth — to Hungary and Bohemia, a settlement that pointed toward the Habsburg future of central Europe. He was buried at Oradea (Nagyvárad) beside the shrine of St Ladislaus, the warrior-king of Hungary he had venerated all his life. With him the House of Luxembourg, which had given the Empire four rulers, ended in the male line.