CYZICUS, an ancient town of Mysia in Asia Minor, situated on the shoreward side of Arctonnesus, which is said to have been originally an island in the Sea of Marmora, and to have been artificially connected with the mainland in historic times. It was, according to tradition, occupied by Thessalian settlers at the corn ing of the Argonauts, and in 756 B.C. the town was founded by Greeks from Miletus. Owing to its advantageous position it speedily acquired commercial importance, and the gold staters of Cyzicus were a staple currency in the ancient world till they were superseded by those of Philip of Macedon. During the Pelopon nesian War (431-404 B.e.) Cyzicus was subject to the Athenians and Lacedaemonians alternately, and at the peace of Antalcidas (387 B.C), like the other Greek cities in Asia, it was made over to Persia. The history of the town in Hellenistic times is closely connected with that of the dynasts of Pergamum, with whose ex tinction it came into direct relations with Rome. Cyzicus was held for the Romans against Mithridates in 74 B.C. till the siege was raised by Lucullus : the loyalty of the city was rewarded by an extension of territory and other privileges. Still a flourishing centre in Imperial times, the place appears to have been ruined by a series of earthquakes. The principal extant ruins are : the walls, which are traceable for nearly their whole extent, a picturesque amphitheatre intersected by a stream, and the sub structures of the temple of Hadrian. Of this magnificent building, sometimes ranked among the seven wonders of the ancient world, thirty-one immense columns still stood erect in See J. Marquardt, Cyzicus (Berlin, 183o) ; G. Perrot, Exploration de la Galatie (Paris, 1862) ; F. W. Hasluck, Cyzicus (191o).