Bohemond I (bō´həmŏnd), c.1056–1111, prince of Antioch (1099–1111), a leader in the First Crusade (see Crusades); elder son of Robert Guiscard. With his father he fought (1081–85) against the Byzantine emperor Alexius I. When his father's duchy of Apulia passed to his younger brother Roger, Bohemond made war against him and obtained S Apulia as a fief. In 1096 he joined the Crusaders. He swore the oath of fealty to Alexius at Constantinople (1097) and in 1098 at the siege of Antioch devised the stratagem by which the city was captured. He subsequently made himself prince of Antioch, in defiance of his oath to Alexius, and over the opposition of Raymond IV of Toulouse, leader of the crusade. Captured by Muslims (1100), he was released in 1103. Returning to Europe, he married the daughter of Philip I of France and secured support for a crusade against Alexius, by whom he was defeated (1108) and as a result was forced to reaffirm his vassalage. In 1109 he was defeated by the Muslims at Harran. He did not return to Antioch, and his relative Tancred was regent for him.
See biography by R. B. Yewdale (1924, repr. 1971).