About 290 Lactantius went to Nicomedia in Bithynia while Diocletian was emperor, to teach rhetoric, but found little work to do in that Greek-speaking city.
In middle age he became a convert to Christianity, and about 306 he went to Gaul (Treves) on the invitation of Constantine the Great, and became tutor to his eldest son, Crispus.
He probably died about 340.
Lactantius' chief work, Divinarum Instilutionum Libri Septem, is an " apology " for and an introduction to Christianity, written in exquisite Latin, but displaying such ignorance as to have incurred the charge of favouring the Arian and Manichaean heresies.
It seems to have been begun in Nicomedia about 304 and finished in Gaul before 311.
The first, De Falsa Religione, and the second, De Origine Erroris, attack the polytheism of heathendom, show the unity of the God of creation and providence, and try to explain how men have been corrupted by demons.
The fifth book, De Justitia, maintains that true righteousness is not to be found apart from Christianity, and that it springs from piety which consists in the knowledge of God.
The sixth book, De Vera Cultu, describes the true worship of God, which is righteousness, 56