announced that Jews had desecrated the host (Eucharistic wafer) and the clergy encouraged mobs to pillage, ransack and burn the Jewish quarter. Nearly the entire Jewish population of Prague (3,000 people) was murdered. Jan Hus, a theologian and rector at the Charles University, preached in Prague. In 1402, he began giving sermons in the Bethlehem Chapel. Inspired by John Wycliffe, these sermons focused on what were seen as radical reforms of a corrupt Church. Having become too dangerous for the political and religious establishment, Hus was summoned to the Council of Constance, put on trial for heresy, and burned at the stake in Constanz in 1415. Four years later Prague experienced its first defenestration, when the people rebelled under the command of the Prague priest Jan Želivský. Hus' death, coupled with Czech proto-nationalism and proto-Protestantism, had spurred the Hussite Wars. Peasant rebels, led by the general Jan Žižka, along with Hussite troops from Prague, defeated Emperor Sigismund, in the Battle of Vítkov Hill in 1420. During the Hussite Wars when Prague was attacked by "Crusader" and mercenary forces, the city militia fought bravely under the Prague Banner. This swallow-tailed banner is approximately , with a red field sprinkled with small white fleurs-de-lis, and a silver old Town Coat-of-Arms in the center. The words "PÁN BŮH POMOC NAŠE" (The Lord is our Relief/Help) appeared above the coat-of-arms, with a Hussite chalice centered on the top. Near the swallow-tails is a crescent-shaped golden sun with rays protruding. One of these banners was captured by Swedish troops during the Battle of Prague (1648), when they captured the western bank of the Vltava river and were repulsed from the eastern bank, they placed it in the Royal Military Museum in Stockholm; although this flag still exists, it is in very poor condition. They also took the Codex Gigas and the Codex Argenteus. The earliest evidence indicates that a gonfalon with a municipal charge painted on it was used for the Old Town as early as 1419. Since this city militia flag was in use before 1477 and during the Hussite Wars, it is the oldest still preserved municipal flag of Bohemia. In the following two centuries, Prague strengthened its role as a merchant city. Many noteworthy Gothic buildings were erected and Vladislav Hall of the Prague Castle was added. Habsburg era In 1526, the Bohemian estates elected Ferdinand I of the House of Habsburg.