The Divine Institutes, Books I-VII by Sr. Mary Francis McDonaldan apologetic work: On False Religion, The Origin of Error, On False Philosophy, True Wisdom and Religion, Concerning Justice, On True Worship, and On the Blessed Life. the "Christian Cicero". Online available.
Lactantius: Divine Institutes by Anthony Bowen et al.riposte to pagan criticism and persecution of Christianity, which came to a head in the 'Great' Persecution of Diocletian in the early fourth century AD. Online available.