The Crusader states were a number of mostly 12th- and 13th-century feudal Christian states created by Western European crusaders in Asia Minor, Greece and the Holy Land, and during the Northern Crusades in the eastern Baltic area. The name also refers to other territorial gains (often small and short-lived) made by medieval Christendom against Muslim and pagan adversaries.

The Crusader states in the Levant—the Kingdom of Jerusalem, the Principality of Antioch, the County of Tripoli, and the County of Edessa[1]—were the first examples of "Europe overseas". Between them, they span the period from 1098 to 1291. They are generally known by historians as Outremer, from the French outre-mer ("overseas" in English).[2][3] French and Latin were used during the Crusades among Western Europeans, distinguishing them from the indigenous Greek and Syriac Christians.