Why did many Christians oppose Frederick II’s rule in Jerusalem?

Many Christians opposed Frederick II’s rule in Jerusalem primarily because he was under a sentence of excommunication by Pope Gregory IX at the time he arrived in the Holy Land. Because he was considered an enemy of the church, his presence and his subsequent actions were viewed with deep hostility by many in the Christian community.12

Key reasons for this opposition included:

• Ecclesiastical Sanctions: Upon Frederick’s arrival in Acre, the patriarch placed Jerusalem under interdict when the excommunicated emperor entered the city.1
• Diplomatic Methods: Frederick secured control of Jerusalem, Bethlehem, and Nazareth through a treaty with the Ayyūbid sultan al-Malik al-Kāmil rather than through military conquest. This diplomatic approach, which included allowing Muslims to retain control of the Temple area and their own justice system, was denounced by the devout of both faiths.12
• Imperial Ambitions: Frederick’s attempt to impose his own imperial administration conflicted with the established power of the local kingdom of Jerusalem baronage, leading to internal civil strife.1