Excommunicated by the Pope yet undeterred, Holy Roman Emperor Frederick II secured Jerusalem, Bethlehem, and Nazareth through diplomacy rather than warfare, an outcome that scandalized crusading zealots on both sides who expected bloodshed, not treaties. The arrangement held an uneasy peace for roughly a decade before the city again changed hands.
Frederick II was an unlikely crusader. Fluent in Arabic, deeply curious about Islamic science and philosophy, and openly skeptical of religious zealotry, he arrived in the Holy Land under a cloud of papal excommunication for having delayed his crusade for years. Rather than storm Jerusalem's walls, he opened correspondence with Sultan al-Kamil of Egypt, a ruler with whom he shared intellectual interests and a mutual distaste for holy war as an end in itself.
The two men negotiated for weeks, exchanging gifts and philosophical letters alongside political terms. The resulting treaty ceded Jerusalem to Christian control, though Muslims retained rights to the Dome of the Rock and al-Aqsa Mosque, an early model of shared religious access that pleased almost no hardliners. Crusader knights and local Christian clergy were reportedly furious that the emperor had won the holy city through negotiation rather than glorious combat.
Frederick crowned himself King of Jerusalem in a ceremony inside the Church of the Holy Sepulchre, with no clergy willing to officiate given his excommunicated status. He placed the crown on his own head. The peace lasted only until 1244, when Jerusalem fell again, but the episode remains one of history's strangest crusades: one that ended not with a siege, but a signature.
Key people: Frederick II, Al-Kamil