Almost nothing is known of Justin's personal history, his name appearing only in the title of his work. He must have lived after Gnaeus Pompeius Trogus whose work he excerpted, and his references to the Romans and Parthians' having divided the world between themselves would have been anachronistic after the rise of the Sassanians in the 3rd century. His Latin appears to be consistent with the style of the 2nd century. Syme, however, argues for a date around AD 390, immediately before the compilation of the Augustan History, and dismisses anachronisms and the archaic style as unimportant, as he asserts readers would have understood Justin's phrasing to represent Trogus's time and not their own.
Justin was the author of an epitome of Trogus's expansive Philippic Histories and Origins of the Entire World and Locations of the Earth (Historiae Philippicae et Totius Mundi Origines et Terrae Situs), which was compiled under the reign of Augustus. His preface explains that he aimed to collect the most important and interesting passages of that work, which has since been lost. Its arguments (prologi) are, however, also preserved in various other authors, such as Pliny the Elder. Trogus's main theme was the rise and history of the Macedonian Empire, and Justin permitted himself considerable freedom of digression by producing an idiosyncratic anthology rather than a proper epitome.
- This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). "Justin". Encyclopædia Britannica (11th ed.). Cambridge University Press.
- Syme, Ronald (1988), "The Date of Justin and the Discovery of Trogus", Historia, No. 37, pp. 358–371.
- Justin's Epitome at The Latin Library, Corpus Scriptorum Latinorum, & Itinera Electronica (Latin)
- Watson's 1853 translation at CSL, the Tertullian Project, & Attalus (English)
- Arnaud-Lindet's 2003 translation at CSL (French)
- Correa's 2003 partial translation at CSL (Spanish)
- Prologi of Pompeius Trogus's work at the Tertullian Project