Frederick II, king of Sicily and German emperor

The election of Frederick II to the Empire in 1211 was due to the support of Innocent III and King Philip Augustus. His rival to the crown was Otto IV of Brunswick, who was seeking an alliance with the Plantagenets, but the coalition was defeated at Bouvines in 1214. Frederick was crowned on the throne of Charlemagne at Aix-la-Chapelle in 1215. He eventually returned to Italy in 1220 to assume the imperial crown in Rome.
Frederick had to renounce Sicily in order to obtain the Empire, and left it to his son Henry, (1 year old, in 1212), and promised to lead the Crusade. But from 1220, he had broken his promise and he retook control of the Norman kingdom. His relations with the Pope deteriorated. His first excommunication came about because of his failure to honour this pledge, but he managed to conquer Jerusalem without fighting, due to his knowledge of Arab diplomacy (1229). But confronted with rebellions, supported by the Pope, in the north of Italy and Germany, he had to abandon his conquest. Excommunicated again in 1239, and then deposed by the Pope in 1245, despite the backing of the king of France Saint Louis, Frederick had to fight against his own son, Henry, who contested his right to imperial power (1231-1242). In all of these conflicts, Frederick relied on the Norman kingdom as a base and for its resources.
A well-read prince and constructor, patron of the arts and wise jurist, he was a worthy successor to the great Norman kings. He behaved like an eastern despot, and he pursued a policy of autocracy and centralization in the Mezziogiorno mainland and in Sicily, very different from feudal monarchies. His court was a place where intellectuals from all over Europe and the Arab world could meet. In order to support his political objectives, he founded the university of Naples in 1226, and like Roger before him, promulgated administrative reform, with the constitution of Melfi in 1231. But the kingdom did not survive his death on 10 December 1250.