The King of Jerusalem was the supreme ruler of the Kingdom of Jerusalem, a Crusader state founded in Jerusalem by the Latin Catholic leaders of the First Crusade, when the city was conquered in 1099.
Godfrey of Bouillon, the first ruler of the Kingdom of Jerusalem, refused the title of king choosing instead the title Advocatus Sancti Sepulchri, that is Advocate or Defender of the Church of the Holy Sepulchre. In 1100 Baldwin I, Godfrey's successor, was the first ruler crowned as king. The crusaders in Jerusalem were conquered in 1187, but their Kingdom of Jerusalem survived, moving the capital to Acre in 1191. Crusaders re-captured the city of Jerusalem in the Sixth Crusade, during 1229–1239 and 1241–1244.
The Kingdom of Jerusalem was finally dissolved with the fall of Acre and the end of the Crusades in the Holy Land in 1291.
Even after the Crusader States ceased to exist, the title of "King of Jerusalem" was claimed by a number of European noble houses descended from the kings of Cyprus or the kings of Naples, and is claimed by the current king of Spain.

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