Astacus
Ἀστακός
Astacus (Ἀστακός: Eth.Ἀστακήνος, Eth. Ἀστάκιος), a city of Bithynia, on the gulf of Astacus, and a colony from Megara and Athens. (Strab. p. 563.) Memnon (Phot. Bibl. 224) says that the first colonists came from Megara, in the beginning of the seventeenth Olympiad, and those from Athens came afterwards. Mela (1.19) calls it a colony of Megara. It appears that this city was also called Olbia; for Scylax (p. 35), who mentions the gulf of Olbia and Olbia, does not mention Astacus; and Strabo, who names Astacus, does not mention Olbia. The mythical story of Astacus being founded by Astacus, a son of Poseidon and the nymph Olbia, favours the supposition of the identity of Astacus and Olbia. (Steph. s. v. Ἀστακός.) Astacus was seized by Doedalsus, the first king of Bithynia. In the war between Zipoetes, one of his successors, and Lysimachus, the place was destroyed or damaged. Nicomedes II., the son of Zipoetes, transferred the inhabitants to his city of Nicomedia (Ismid), B.C. 264. Astacus appears to have been near the head of the gulf of Astacus, and it is placed by some geographers at a spot called Ovaschik, and also Bashkele.
Nicomedia was not built on the site of Astacus [NICOMEDIA]; it is described by Memnon as opposite to Astacus.
From William Smith (ed.), Dictionary of Greek and Roman Geography. Text provided under a CC BY-SA license by Perseus Digital Library, http://www.perseus.tufts.edu, with funding from the National Endowment for the Humanities and Tufts University. Data accessed from https://github.com/PerseusDL/canonical-pdlrefwk/ on 17 October 2026.