a friend of J. Caesar, and afterwards quaestor of Antony in B. C. 40. (Cic. Phil. 13.2; Appian, App. BC 5.31.) His name occurs on a coin of Antony: the obverse of which is M. ANT. IMP. AVG. IIIVIR. R. P. C., M. BARBAT. Q. P., where there can be little doubt that M. BARBAT. signifies M. Barbatius, and not Barbatus, as Ursinus and others have conjectured, who make it a surname of the Valeria gens. The letters Q. P. probably signify Quaestor Propraetore. (Comp. Eckhel, v. p. 334.)

This M. Barbatius appears to be the same as the Barbarius Philippus mentioned by Ulpian (Dig. 1. tit. 14. s. 3), where Barbarius is only a false reading for Barbatius, and also the same as the Barbius Philippicus, spoken of by Suidas. (s. v.) We learn from Ulpian and Suidas that M. Barbatius was a runaway slave, who ingratiated himself into the favour of Antony, and through his influence obtained the praetorship under the triumvirs. While discharging the duties of his office in the forum he was recognized, we are told, by his old master, but privately purchased his freedom by a large sum of money. (Comp. Garaton. ad Cic. Phil. 13.2.)