Krak des Chevaliers (French for Castle of Knights; Arabic: Qalaat Al-Hosn) is the largest fortress built by the Crusaders in Syria and one of the greatest surviving examples of medieval military architecture. Built on the site of an earlier Arab stronghold, the fortress is located near the central Syrian city of Homs, close to the Lebanese border. It was built by the Hospitallers, who held it between 1142 and 1271, when it was captured by Sultan Baybars of the Memluks.