Nicomedes I of Bithynia

Introduction

Nicomedes I (Νικομήδης; c. 300–c. 255 BC) was the second king of Bithynia, son and successor of Zipoetes I, ruling from 278 BC until about 255 BC. He secured the throne immediately after his accession by eliminating two brothers; a third brother, Zipoetes II, then carved out independent control over much of Bithynia and mounted a sustained revolt. Facing external pressure from Antiochus I Soter of the Seleucid Empire, Nicomedes formed alliances with Heraclea Pontica and with Antigonus II Gonatas to deter invasion; Antiochus subsequently invaded but withdrew without major battle.

To defeat his internal rival Nicomedes enlisted Gallic forces under Leonnorius and Lutarius, facilitating their crossing into Asia and subsequently using them to defeat and kill Zipoetes II, thereby reunifying Bithynia under his rule; those Gauls later established Galatia in Anatolia. During his long rule Bithynia grew in power and prosperity. Emulating other Hellenistic rulers, Nicomedes founded a new capital, Nicomedia, on a site near the Megarian colony Astakos; Eusebius places its foundation in 264 BC. He married twice; by his first wife Ditizele he had two sons, Prusias and Ziaelas, and a daughter, Lysandra. Under the influence of his second wife, Etazeta, he sought to exclude the children of the first marriage in favor of her offspring and entrusted the guardianship of these infants to Antigonus II and Ptolemy II together with the free cities Heraclea Pontica, Byzantium and Cius. Nicomedes died around 255 BC, after which his son Ziaelas nonetheless moved quickly to seize the throne.