The Kingdom of Jerusalem, also known as the Latin Kingdom, was a Crusader state that was established in the Levant immediately after the First Crusade. It lasted for almost two hundred years, from the accession of Godfrey of Bouillon in 1099 until the fall of Acre in 1291. Its history is divided into two periods with a brief interruption in its existence, beginning with its collapse after the siege of Jerusalem in 1187 and its restoration after the Third Crusade in 1192.

The Crusader states, or Outremer, were four Catholic polities that existed in the Levant from 1098 to 1291. Following the principles of feudalism, the foundation for these polities was laid by the First Crusade, which was proclaimed by the Latin Church in 1095 in order to reclaim the Holy Land after it was lost to the 7th-century Muslim conquest. Situated on the Eastern Mediterranean, the four states were, in order from north to south: the County of Edessa (1098–1150), the Principality of Antioch (1098–1268), the County of Tripoli (1102–1289), and the Kingdom of Jerusalem (1099–1291). The three northern states covered an area in what is now southeastern Turkey, northwestern Syria, and northern Lebanon; and the Kingdom of Jerusalem, the southernmost and most prominent state, covered an area in what is now Israel, Palestine, southern Lebanon, and western Jordan. The description "Crusader states" can be misleading, as from 1130 onwards, very few people among the Franks were Crusaders. Medieval and modern writers use the term "Outremer" as a synonym, derived from the French word for overseas.