The precise chronology of Vegetius is doubtful. The most prevalent theories propose two alternatives: that Vegetius was active at the time of Theodosius, or that he was active in the middle of the fifth century, at the time of Valentinian III. Either of these two suggestions about Vegetius’ date is are stubbornly supported by its defenders, but the positive facts are as follows: the terminus post quem for the composition of Vegetius’ military treaty is the death of Gratian, 25 August 383, and the terminus ante quem is the year 450, which is the date of a copy of the work made by Flavius Eutropius in Constantinople; the date 450 is present in a subscriptio transmitted in the manuscript tradition.
It is also discussed whether Vegetius was active in the Western or Eastern part of the Empire. John Lydus asserts that Vegetius was a Roman writer and approaches his name to that of other writers in the Latin tradition such as Cato, Celsus, Frontinus or Tarruntenus Paternus. Vegetius himself, in the preface of his work, states that he only compiled texts from the Latin literary culture. These clues suggest that he was active in the Western part of the Empire.
The manuscript tradition of the Epitoma rei militaris presents Vegetius as a uir illustris, which seems to fit the familiarity with which he addresses the Emperor in his work. Consequently, it seems quite likely that Vegetius should be considered a member of the late-antique aristocracy that occupied the highest positions of the imperial administration.
The literary legacy of Vegetius includes two works: the Epitoma rei militaris, a polemologic treaty in four books, in which the author summarizes the precepts of the whole Roman military science in order to enable the army of his time to recover the traditional Roman military virtues; and the Digesta artis mulomedicinalis, a veterinarian treatise in three books, also written for the purpose of summarizing all the previous Latin tradition and to enrich it with information obtained directly from veterinarians and doctors.
Until very recently scholars thought that the Vegetius’ veterinary treatise included four books, but the fourth book has been actually found to be a separate short work on bovine diseases, entitled De curis boum epitoma (ex diuersis auctoribus). [D. Paniagua; tr. L. Battezzato]