It was located on the shoreward side of the present Kapıdağ Peninsula (the classical Arctonnesus), a tombolo which is said to have originally been an island in the Sea of Marmara only to be connected to the mainland in historic times either by artificial means or an earthquake.

The city was said to have been founded by Pelasgians from Thessaly, according to tradition at the coming of the Argonauts; later it received many colonies from Miletus, allegedly in 756 BC, but its importance began near the end of the Peloponnesian War when the conflict centered on the sea routes connecting Greece to the Black Sea.

Famed ancient philosopher Eudoxus of Cnidus established a school at Cyzicus and went with his pupils to Athens, visiting Plato.

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commercial importance, and the gold staters of Cyzicus were a staple currency in the ancient world till they were superseded by those of Philip of Macedon.

The history of the town in Hellenistic times is closely connected with that of the Attalids of Pergamon, with whose extinction it came into direct relations with Rome.

Under Tiberius, it was incorporated into the Roman Empire but remained the capital of Mysia (afterwards, Hellespontus) and became one of the great cities of the ancient world.

Although its population was transferred to Artake before the 13th century when the peninsula was occupied by the Crusaders,[3] in 1324 the metropolitan of Cyzicus was one of three sees in Anatolia which was able to contribute a temporary annual subsidy to the Patriarchate of Constantinople.

In the Notitiae Episcopatuum of Pseudo-Epiphanius, composed in about 640, Cyzicus had 12 suffragan sees; Abydus, Baris in Hellesponto (between Sariköy and Biga), Dardanus, Germa in Hellesponto (ruins of Germaslu, Kirmasti, Girmas), Hadrianotherae (Uzuncia yayla), Ilium, Lampsacus, Miletopolis, Oca, Pionia (Avcılar), Poemanenum (Eskimanias), Troas.

Of this magnificent building, sometimes ranked among the seven wonders of the ancient world, thirty-one immense columns still stood erect in 1444.

[24] The monuments of Cyzicus were used by the Byzantine emperor Justinian as a quarry for the building of his Saint Sophia cathedral, and were still exploited by the Ottomans.