Archelaus, a Cappadocian, the distinguished general of Mithridates VI, flourished in the 1st century B.C. After defeating Nicomedes II at Amnias, 88 B.C., he sailed to Greece, captured Delos and other towns, and induced Achaia, Lacedemon, and Boeotia to form an alliance with Mithridates against Rome. Sulla besieged him in the Piraeus, and compelled him to withdraw his forces. Returning to the contest with a still larger army, Archelaus was again defeated, and forced to retire when, acting upon instructions received from Mithridates, he concluded peace with Sulla, but upon terms unsatisfactory to the king. He finally deserted to the Romans, after which little is known of him.