Godfrey de Bouillon
Godfrey de Bouillon was one of the leaders of the First Crusade and it was an incredible success. They achieved their objective of conquering Jerusalem from the Muslims in 1099 CE. Godfrey de Bouillon was elected King of Jerusalem by the other Crusaders that same year, but being one of the less self interested Crusaders he declined the title, feeling that it was too great an honor. Instead he became the "Advocatus Sancti Sepulchri". He remained the supreme ruler of the Kingdom of Jerusalem until his death on the 18th of July 1100 CE.
Although Godfrey de Bouillon was never crowned King of Jerusalem he is sometimes referred to as the King of the Crusaders. His brother Baldwin I was officially crowned as the first King of Jerusalem on the 25th of December 1100 CE, in Bethlehem.