6. A king of Galatia and several of the adjacent countries, mentioned by Strabo (xii. p.569) as contemporary with himself. He seems to have first possessed Lycaonia, where he maintained more than 300 flocks. (Strab. xii. p.568.) To this he added the territory of Derbe by the murder of its prince, Antipater, the friend of Cicero (Cic. Fam. 13.73), and Isaura and Cappadocia by Roman favour. Plutarch, who enumerates him among the adherents of Antony at Actium (Ant. p. 944c.), speaks probably by anticipation in calling him king of Galatia, for he did not succeed to that till the death of Deiotarus (Strab. xii. p.567); and the latter is mentioned by Plutarch himself (Ant. p. 945b.) as deserting to Octavius, just before the battle, together with Amyntas.

While pursuing his schemes of aggrandizement, and endeavouring to reduce the refractory highlanders around him, Amyntastas made himself master of Homonada (Strab. xii. p.569), or Homona (Plin. Nat. 5.27), and slew the prince of that place; but his death was avenged by his widow, and Amyntas fell a victim to an ambush which she laid for him. (Strab. l.c.)