This region was organized circa 281 BC as a kingdom by Mithridates I of Pontus, whose ancestry line dated back to Ariobarzanes I, a Persian ruler of the Greek town of Cius. The most prominent descendant of Mithridates I was Mithridates VI Eupator, who between 90 and 65 BC fought the Mithridatic Wars, three bitter wars against the Roman Republic, before eventually being defeated. Mithridates VI the Great, as he was left in memory, claiming to be the protector of the Greek world against the barbarian Romans, expanded his kingdom to Bithynia, Crimea and Propontis (in present-day Ukraine and Turkey) before his downfall after the Third Mithridatic War.