Conrad IV of Germany

Frederick deposed Conrad's older brother Henry, and had Conrad elected king of the Romans[?] in 1237, with Archbishop Siegfried II of Mainz acting as regent until 1241, when Henry Raspe[?], Landgrave of Thuringia took over. However, Pope Innocent IV, elected in 1243, had Raspe elected as anti-king in Germany in 1246, passing the crown to William of Holland when Raspe died in 1247.

When Frederick died in 1250, he passed Sicily and Jerusalem to Conrad, but the struggle with the pope continued, with Conrad invading Italy in 1251, but not with enough success to subdue the pope's supporters, and in turn the pope offered Sicily to Edmund, son of Henry III of England (1253).

Conrad was excommunicated in 1254, but died of a fever in the same year, and it was left to his son Conradin to continue the struggle with the Papacy.