The Jews and Muslims fought together to defend Jerusalem against the invading Franks. They were unsuccessful though and on 15 July 1099 the crusaders entered the city. They proceeded to massacre the remaining Jewish and Muslim civilians and pillaged or destroyed mosques and the city itself. After gaining control of Jerusalem the Crusaders created four Crusader states: the Kingdom of Jerusalem, the County of Edessa, the Principality of Antioch and the County of Tripoli.
Kingdom of Jerusalem founded by Godfrey of Bouillon. From offense to defense, new fortresses build in Jerusalem and some of them seen till now. On the next years, the orders of Knights founded basic on military and religion. Knights Templars and Knights Hospitaler are the most popular. On the beginning, they founded to help the crusader, they become strong military organization and stand-alone. Kingdom of Jerusalem falls on October 1187, defeated by Saladin.