Almost nothing is known of Justin's personal history, his name appearing only in the title of his work. He must have lived afterGnaeus Pompeius Trogus, whose work he excerpted, and his references to theRomans andParthians having divided the world between themselves would have been anachronistic after the rise of theSassanians in the third century. HisLatin appears to be consistent with the style of the second century.Ronald Syme, however, argues for a date around 390, immediately before the compilation of theAugustan History, and dismisses anachronisms and the archaic style as unimportant, as he asserts that readers would have understood Justin's phrasing to represent Trogus' time, and not his own.[1]
Justin was the author of anepitome of Trogus' expansiveLiber Historiarum Philippicarum, orPhilippic Histories, a history of the kings ofMacedon, compiled in the time ofAugustus. Due to its numerous digressions, this work was retitled by one of its editors,Historia Philippicae et Totius Mundi Origines et Terrae Situs, orPhilippic History and Origins of the Entire World and All of its Lands. Justin'spreface explains that he aimed to collect the most important and interesting passages of that work, which has since been lost. Some of Trogus' original arguments (prologi) are preserved in various other authors, such asPliny the Elder. Trogus' main theme was the rise and history of theMacedonian Empire, and like him, Justin permitted himself considerable freedom of digression, producing an idiosyncratic anthology rather than a strict epitome.
^Justin's name is given only in manuscripts of his own history, the majority of which simply identify him asJustinus. One manuscript identifies him asJustinus Frontinus, the other asMarcus Junianus Justinus. The accuracy of these names is uncertain.