The Sixth Crusade recovered Jerusalem by treaty in 1229.
Led by Emperor Frederick II, the largely diplomatic crusade ended with the Treaty of Jaffa, agreed on 18 February 1229. Frederick negotiated with al-Kamil, the Ayyubid sultan of Egypt, who was under pressure from rival members of his own family and therefore had reasons to reach an agreement.
The treaty returned Jerusalem, Bethlehem, Nazareth, and a corridor linking Jerusalem with the crusader coast to the Kingdom of Jerusalem. Muslim control of the Temple Mount and its holy sites remained intact, however, and the agreement established a truce lasting ten years, five months, and forty days. Frederick entered Jerusalem on 17 March 1229.
A common misconception is that the Sixth Crusade captured the city in a major battle. In reality, Frederick’s army was too small for a reliable military victory, and the recovery was achieved through negotiation. The treaty was controversial: some Christian leaders viewed it as a diplomatic triumph, while others condemned its concessions and Frederick’s excommunication.