Of his personal history nothing is known. He is the author of Historiarum Philippicarum libri XLIV, a work described by himself in his preface as a collection of the most important and interesting passages from the voluminous Historiae pillippicae et totius mundi origines et terrae situs, written in the time of Augustus by Pompeius Trogus.
The work of Trogus is lost; but the prologi or arguments of the text are preserved by Pliny and other writers. Although the main theme of Trogus was the rise and history of the Macedonian monarchy, Justin yet permitted himself considerable freedom of digression, and thus produced a capricious anthology instead of a regular epitome of the work.
As it stands, however, the history contains much valuable information. The style, though far from perfect, is clear and occasionally elegant. The book was much used in the middle ages, when the author was sometimes confounded with Justin Martyr.
This entry was originally from the 1911 Encyclopedia Britannica.