The Crusader Kingdoms developed mainly on the Mediterranean coast from where they were supplied and reinforced; however, the constant raids launched by the surrounding unhappy Arab population meant the cost of occupation would not be cheap. The feudal kingdoms established in Palestine never had a chance of succeeding in the long-term.
Orders of Christian warrior-monks formed to fight and protect the Crusader Kingdoms in the Holy Lands. The Knights Hospitaller were formed in 1113 immediately following the capture of Jerusalem. Their purpose was to serve and care for Christian pilgrims travelling from Europe to Palestine. In 1119 AD the Knights Templar was established. The Templars stressed the virtues of poverty, discipline and obedience. The Teutonic Knights were German and cared for German-speaking peoples travelling to the Holy Land. The Teutonic Knights were the fiercest and most determined of the orders. Yet, there were never enough Teutons to control Palestine once and for all.
The Crusader Kingdoms in Palestine survived for a while in part because they learned to negotiate, compromise, and play the different Arab groups off one another. Eventually a great Arab leader appeared who united all the Islamic groups under one banner. His name was Saladin.
Saladin became Sultan of Egypt and Syria in 1174 AD. In 1187, he won a great victory over the Crusaders in the desert and recaptured Jerusalem after the Battle of Hattin. Over the next one-hundred years, Europeans made several attempts to retake the Holy Land but failed.
Following the fall of the Kingdom of Jerusalem Muslim armies attacked the remaining Crusader Kingdoms. Gradually the Christian presence in Palestine was reduced to a few narrow pockets of resistance along the coastline. Although a Christian presence remained in the Middle East well into the 13th and 14th Centuries, the power and influence of the crusaders was effectively broken. The island of Cyprus was the last crusader territory to fall (captured by the Ottoman Turks in 1571).