The Crusader states were a series of feudal territories established by European Christians in the Levant during the Middle Ages, following the First Crusade in 1096. These states included the Kingdom of Jerusalem, the County of Edessa, the Principality of Antioch, and the County of Tripoli. They served as military and religious outposts aimed at securing Christian control over the Holy Land. These states existed from the late 11th century until the late 13th century, facing constant threats from Muslim forces. The Fall of Acre in 1291 marked the end of the Crusader states, leading to the decline of Christian political power in the region.