(Ἀντίοχος), king of COMMAGENE, a small country between the Euphrates and mount Taurus, the capital of which was Samosata. It formerly formed part of the Syrian kingdom of the Seleucidae, but probably became an independent principality during the civil wars of Antiochus Grypus and his brother. It has been supposed by some, that Antiochus Asiaticus, the last king of Syria, is the same as Antiochus, the first king of Commagene; but there are no good. reasons for this opinion. (Clinton, F.H. iii. p. 343.) This king is first mentioned about B. C. 69, in the campaign of Lucullus against Tigranes. (Dio Cass. Frag. 35.2.)

After Pompey had deposed Antiochus Asiaticus, the last king of Syria, B. C. 65, he marched against Antiochus of Commagene, with whom he shortly afterwards concluded a peace. (B. C. 64.) Pompey added to his dominions Seleuceia and the conquests he had made in Mesopotamia. (Appian, App. Mith. 106, 114.) When Cicero was governor of Cilicia (B. C. 51), he received from Antiochus intelligence of the movements of the Parthians. (Cic. Fam. 15.1, 3, 4.) In the civil war between Caesar and Pompey (B. C. 49), Antiochus assisted the latter with troops. (Caesar, Caes. Civ. 3.5; Appian, App. BC 2.49.) In B. C. 38, Ventidius, the legate of M. Antonius, after conquering the Parthians, marched against Antiochus, attracted by the great treasures which this king possessed; and Antonius, arriving at the army just as the war was commencing, took it into his own hands, and laid siege to Samosata. He was, however, unable to take the place, and was glad to retire after making peace with Antiochus. (D. C. 49.20_22; Plut. Ant. 34.) A daughter of Antiochus married Orodes, king of Parthia. (D. C. 49.23.) We do not know the exact period of the death of Antiochus, but he must have died before B. C. 31, as his successor Mithridates is mentioned as king of Commagene in that year. (Plut. Ant. 61.)