ABYDOS, ancient town of Mysia, Asia Minor, on the Hellespont, here scarcely a mile broad. Probably originally a Thracian town, it was afterwards colonized by Milesians. Here Xerxes crossed the strait on his bridge of boats when he invaded Greece. Abydos is celebrated for its vigorous resistance to Philip V. of Macedon (200 B.c.), and is famed in story for the loves of Hero and Leander. Until late Byzantine times the toll station of the Hellespont, its importance was transferred to the Dardanelles (q.v.), after the building of the "Old Castles" by Sultan Moham med II. (c. 1456).