Valentinus (mid-2nd century CE) was the founder of what came to be one of the most influential Gnostic sects of heretical Christianity. Little can be known with certainty about either his life or his teachings, apart from what has been preserved for us in the writings of the church fathers, much of which is reported only very sketchily, with a view toward refutation. The discovery, in 1945, of important Coptic texts at Nag Hammadi has improved our understanding of his thought, but the texts discovered there (principally the so-called Evangelium Veritatis [Gospel of truth]) represent the thought of the various schools drawing inspiration from his teachings and cannot reasonably be attributed to Valentinus himself. St. Irenaeus (Adversus Haereseis I) and others assert that he was a native of Egypt, where he is said to have studied under Theodas, alleged to have been a pupil...