Latin historian, whose name appears in some manuscripts as M. Junianus Justinus, and in others, Justinus Frontinus. We are unable to fix with precision the period during which he flourished, though some have placed him in the reign of Antoninus, A.D. 160, from the name of that emperor being found in the dedication according to some manuscripts, though it is doubted whether this dedication be genuine. Of his private history we know nothing. Justin abridged the history of Trogus Pompeius, who wrote in the reign of Augustus. Its title runs thus: Historiarum Philippicarum, et totius mundi originium et terrae situs ex Trogo Pompeio excerptarum, libri xiv. a Ninoad Caesarem Augustum. The first six books may be considered as an introduction to the history of Macedonia, which is found in books vii. viii. ix. xi.—xvii. xxiv.—xxvi. xxviii.—xxx xxxiii. Justin tells us that he omitted every thing which he considered as either unnecessary or likely to be displeasing to the reader, and in this way he has passed over all the geographical information of Trogus. He is particularly deficient in chronological arrangement, though his style is in general simple and correct. The Prologi which are found attached to each book were not written by Justin, but by some old grammarian. Editio princeps, Venet. 1470, per Jenson, and Rome, 1470, 1471. It has often been published along with Florus: Mediol. 1476; ed. Bougasius, Par. 1581; ed. Lemaire, Par. 1823; & recens. Gron. et cum var. not. ed. Frotscher, Lips. 1827, 3 vols.