into the shafts of disused silver mines. King Wenceslaus swore death to all the rebels, but died of a stroke in August, 1419. The next months were marked by deeds of violence; many citizens, especially Germans, had to flee. Wenceslaus was succeeded by his brother Sigismund, King of the Romans and King of Hungary, who prepared to restore order. On 1 March 1420, Pope Martin V issued a Bull inviting all Christians to unite in a crusade against the Wycliffites (Lollards), Hussites, and other heretics. The crusades were, however, ultimately unsuccessful. Crusades According to Burton, Pope Martin authorized a crusade against Africa in 1418 in relation to the slave trade. In addition to the Hussite Crusades, Martin declared a Crusade against the Ottoman Empire in 1420 in response to the rising pressure from the Ottoman Turks. In 1419–1420 Martin had diplomatic contacts with the Byzantine emperor Manuel II, who was invoking a council in Constantinople. On 12 July 1420 the Pope conceded to attach an indulgence to anyone who would contribute to a crusade against the latter, which would be led by Sigismund, King of the Romans. War against Braccio da Montone The main concern of Martin's pontificate from 1423 was the resumed war against Braccio da Montone. The following year, the combined Papal-Neapolitan army, led by Giacomo Caldora and Francesco Sforza, defeated him at the Battle of L'Aquila (2 June 1424); Braccio died a few days later. In the same year Martin obtained a reduction of the autonomy of the commune of Bologna, whose finances would be thenceforth under the authority of a papal treasurer. He also ended the war with Braccio da Montone in exchange for his recognition as vicar and reconciled with the deposed John XXIII, to whom he gave the title of Cardinal of Tusculum. Annuity contracts Canon law prohibited interest upon a loan. To avoid this, annuities were paid, interest in effect but not in name. The dispute as to the legality of annuity contracts was brought before Martin V in 1423. He held that purchased annuities, which were redeemable at the option of the seller, were lawful. When the lawfulness of annuities was established, they were widely used in commerce; it seems that city states used them to raise compulsory loans from their citizens. Periodic ecumenical councils A decree of the Council of Constance ordered that councils should be held every five years. Martin