Nicomedes IV Philopator: last king of independent Bithynia (r.94-77 BCE).
Nicomedes IV Philopator, a son of Nicomedes III Euergetes and Nysa of Cappadocia, inherited the Bithynian throne in an unquiet age, with Mithridates VI of Pontus as a dangerous neighbor. He supported Socrates Chrestus, a half-brother of Nicomedes, against him and in the end, Nicomedes was forced to flee to Italy, to Rome, where asked the Senate for support. He was brought back by Roman troops and sought revenge by invading Pontus, which only meant that Mithridates attacked him and made him flee to Rome again. This was one of the causes of the First Mithridatic War (89/98-85 BCE).
In 84, after the defeat of Mithridates, Nicomedes could return. Bithynia was now essentially a protectorate of Rome, and in his will, he bequaethed his kingdom to Rome (77 BCE). It was immediately invaded by Mithridates: the cause of the Third Mithridatic War (83-63).