By the beginning of the 13thcentury Papal reticence in applying crusades against the papacy's political opponents and those considered heretics. Innocent III proclaimed a crusade against Catharism that failed to suppress the heresy itself but ruined the culture the Languedoc. This set a precedent that was followed in 1212 with pressure exerted on the city of Milan for tolerating Catharism, in 1234 against the Stedinger peasants of north-western Germany, in 1234 and 1241 Hungarian crusades against Bosnian heretics. The historian Norman Housley notes the connection between heterodoxy and anti-papalism in Italy. Indulgence was offered to anti-heretical groups such as the Militia of Jesus Christ and the Order of the Blessed Virgin Mary. Innocent III declared the first political crusade against Frederick II's regent, Markward von Annweiler, and when Frederick later threatened Rome in 1240, Gregory IX used crusading terminology to raise support against him. On Frederick II's death the focus moved to Sicily. In 1263, Pope Urban IV offered crusading indulgences to Charles of Anjou in return for Sicily's conquest. However, these wars had no clear objectives or limitations, making them unsuitable for crusading. The 1281 election of a French pope, MartinIV, brought the power of the papacy behind Charles. Charles's preparations for a crusade against Constantinople were foiled by the Byzantine Emperor Michael VIII Palaiologos, who instigated an uprising called the Sicilian Vespers. Instead, Peter III of Aragon was proclaimed king of Sicily, despite his excommunication and an unsuccessful Aragonese Crusade. Political crusading continued against Venice over Ferrara; Louis IV, King of Germany when he marched to Rome for his imperial coronation; and the free companies of mercenaries.