
Ayyubid ruler of Damascus during Fifth Crusade.
Al-Muazzam Isa, as Ayyubid ruler of Damascus, participated in the defense against the Fifth Crusade. The Crusaders besieged Damietta in the Nile Delta. Al-Muazzam Isa's forces were unable to prevent the city's fall in 1219, leading to a temporary Crusader occupation.
Al-Muazzam Isa, alongside his brother Sultan Al-Kamil of Egypt, negotiated the end of the Fifth Crusade. The treaty restored Damietta to the Ayyubids in exchange for a truce and the Crusaders' withdrawal from Egypt. This secured Ayyubid control over the region.
Al-Muazzam Isa engaged in a power struggle with his brother Sultan Al-Kamil of Egypt. He allied with the Khwarezmian prince Jalal al-Din against Al-Kamil. This internal Ayyubid conflict weakened the dynasty and allowed Crusader states to regain territory.
Al-Muazzam Isa died in Damascus, likely from natural causes. His death ended his rivalry with Al-Kamil and allowed the Egyptian sultan to consolidate Ayyubid power. His son An-Nasir Dawud succeeded him but was later deposed by Al-Kamil.