The Al-Aqsa Mosque is a holy mosque, important to Muslims, located in Jerusalem.
After Jerusalem was captured in 1099 as part of the First Crusade, the Kingdom of Jerusalem was established, and the Al-Aqsa Mosque was used as the royal palace of the Kings of Jerusalem. The Crusaders believed it to be built on top of the ruins of the King Solomon's Temple, and referred to the building as the Templum Salomonis, while the Dome of the Rock was called Templum Domini (The Temple of the Lord).
Around 1119, King Baldwin II of Jerusalem also granted space in one wing to the a new order, which after this centre was called of the Knights Templar. The Templars used the building as their headquarters until Saladin conquered the city in 1187, at which point the Templars moved their headquarters to the northern coastal city of Acre, which they held for the next 100 years, and then the island of Cyprus after that.