Frederick II Holy Roman Empror

Pope Innocent III, who feared the threat posed by a union of the empire and Sicily, was now supported by Frederick II, who marched to Germany and defeated Otto. After his victory, Frederick did not act upon his promise to keep the two realms separate. Though he had made his son Henry king of Sicily before marching on Germany, he still reserved real political power for himself. This continued after Frederick was crowned Emperor in 1220. Fearing Frederick's concentration of power, the Pope finally excommunicated the Emperor. Another point of contention was the crusade, which Frederick had promised but repeatedly postponed.