Pope Gregory IX
On July 25 1215 Federico was crowned king of the romans in Aquisgrana. He wanted to band the crusade, but nothing happened for years, he became emperor in 1220, and the new Pope Gregorio IX excommunicate him. Frederick was forced to leave, but his was a particular enterprise: instead of fighting, he began a long negotiation with the enemy, the Sultan of Egypt, getting delivery of Jerusalem, Bethlehem, Nazareth and movement guarantees for pilgrims. During negotiations he entertained in philosophical and scientific discussions with Muslim scholars, which the critical procured and disbelief accusations.