The three Military Orders, the Teutonic Knights, Knights Templars and Hospitaliers, each came into being in the Kingdom of Jerusalem in the 12th century. The Templars and Hospitaliers were already well established by the end of the Third Crusade, while the Teutonic Knights were established as a chivalric order during the German crusade in March 1198. The position of the Teutonic knights was enhanced by their wholehearted support of the Holy Roman Emperor, Frederick II, in the Sixth Crusade, when the return of Jerusalem into Christian hands was negotiated with its Ayyubid occupiers. However, all the military orders were expelled when the Khwarezmian Turks took the city in 1244. After overcoming the Mongols just south of Acre in 1260, the Mamluks picked off the remaining strongholds of the military orders, culminating in the capture of Acre in 1291, effectively spelling the end of the crusading era.