Nicomedes I of Bithynia

King Zipoetes of Bithynia died in 278, after a reign of almost half a century, in which he had been able to maintain his independence. seventy-six years old. His son Nicomedes I succeeded him and immediately killed all his brothers, although Zipoetes II managed to escape and fought a civil war against his elder brother.

Nicomedes inherited a conflict with the Seleucid king Antiochus I Soter and allied himself to Antigonus II Gonatas of Macedonia, but in the end, the Seleucid invasion was broken off before it threatened the Bithynian independence. Nicomedes could now focus on his brother and sought new allies: the Galatians, bands of Celtic warriors who had already created havoc in southwestern Europe. Nicomedes transferred them to Asia and used them against Zipoetes, who was captured in 276 and executed. The Galatians migrated to the center of Anatolia.

In 264 BCE, Nicomedes founded Nicomedia on the site of Astacus, a colony of the Greek city of Megara. When he died, nine years later, he had sons from two marriages: from Ditizele, a lady from Hellespontine Phrygia, he had sons named Ziaelas and Prusias, and several other children from his second wife Etazeta. Nicomedes preferred the younger children and passed over Ziaelas, who went into exile in Armenia, where he was received by a king who may be identified with Samus.^note[Memnon of Heracles, fragment 14.] After his father's death, civil war broke out.