in Ancient Geography, a town of Mysia, in Asia Minor, situated on the narrowest part of a considerable peninsula which juts out into the Propontis on its southern shore. This peninsula was at one time an island, and was believed to have been joined to the mainland by Alexander the Great with moles and bridges. During the Peloponnesian war, Cyzicus was alternately subject to the Athenians and Lacedemonians, as the power of either state predominated. At this period, however, it was a very unimportant place. At the peace of Antalcidas, Cyzicus, like the other Greek cities in Asia, was made over to Persia. The greatness and prosperity of the town did not commence till about B.C. 74, when the Cyzicenes, under circumstances of great difficulty, repelled Mithridates from their walls, and kept the town till relieved by Lucullus. For their bravery and devotion at this time they were rewarded with peculiar honours and privileges by the Romans, and presented with a large tract of the rich land adjoining their city. Cyzicus was seriously injured by an earthquake in the reign of Antoninus Pius, and from that period gradually declined. The ruins of Cyzicus, which once boasted a very large number of splendid temples and public buildings, are still traceable among the orchards and vineyards that have overgrown its site.