Nicomedes I of Bithynia

Nicomedes I (Greek: Nικoμήδης; lived c. 300 BC – c. 255 BC, ruled 278 BC – c. 255 BC), second king of Bithynia, was the eldest son of Zipoetes I, whom he succeeded on the throne in 278 BC.

He commenced his reign by putting to death two of his brothers but the third, subsequently called Zipoetes II, raised an insurrection against him and succeeded in maintaining himself, for some time, in the independent sovereignty of a considerable part of Bithynia. Meanwhile, Nicomedes was threatened with an invasion from Antiochus I Soter, king of the Seleucid Empire, who had already made war upon his father, Zipoetes I, and, to strengthen himself against this danger, he concluded an alliance with Heraclea Pontica and shortly afterwards with Antigonus II Gonatas. The threatened attack, however, passed over with little injury. Antiochus actually invaded Bithynia but withdrew again without risking a battle.

It was more against his brother than his foreign enemies that Nicomedes now called in the assistance of more powerful auxiliaries and entered into an alliance with the Celts who, under Leonnorius and Lutarius, had arrived on the opposite side of the Bosphorus and were, at this time, engaged in the siege of Byzantium, 277 BC. Having furnished them with the means of crossing into Asia, where they founded Galatia, he first turned the arms of his new auxiliaries against Zipoetes II, whom he defeated and put to death, and thus reunited the whole of Bithynia under his dominion.

Of the events that followed we have little information. It is probable that the Celts subsequently assisted Nicomedes against Antiochus but no particulars are recorded, either of the war or the peace that terminated it. It appears, however, that Nicomedes was left in the undisturbed possession of Bithynia, which he continued to govern from this time till his death and which rose to a high degree of power and prosperity during his long and peaceful reign.

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