Frederick II (26 December 1194 – 13 December 1250), was one of the most powerful Holy Roman Emperors of the Middle Ages and head of the House of Hohenstaufen. His political and cultural ambitions, based in Sicily and stretching through Italy to Germany, and even to Jerusalem, were enormous. However, his enemies, especially the popes, prevailed, and his dynasty collapsed soon after his death. Historians have searched for superlatives to describe him, as in the case of Professor Donald Detwiler, who wrote: 