Valentinus (Greek: Οὐαλεντῖνος), also spelled Valentinius; AD 100 – 180, was the best known and, for a time, most successful early Christian Gnostic theologian. He founded his school in Rome. According to Tertullian, Valentinus was a candidate for bishop but started his own group when another was chosen.
Valentinus produced a variety of writings, of which for the most part only fragments quoted by his opponents survive. However, it has recently been argued that
Valentinus's lost letter to Agathapous, quoted by Clement of Alexandria, is in fact Letter 366 of Pseudo-Basil. Some have also argued that the Gospel of Truth, a work preserved in the Nag Hammadi library, is also from the pen of Valentinus. Otherwise, his doctrine is known only in the developed and modified form given to it by his disciples, the Valentinians.
Valentinus taught that there were three kinds of people, the spiritual, psychical, and material; and that only those of a spiritual nature received the gnosis (knowledge) that allowed them to return to the divine Pleroma, while those of a psychic nature (ordinary Christians) would attain a lesser or uncertain form of salvation, and that those of a material nature were doomed to perish.
Valentinus had a large following, the Valentinians. It later divided into an Eastern and a Western, or Italian, branch. The Marcosians belonged to the Western branch.
Epiphanius wrote (390) that he learned through word of mouth (although he acknowledged that it was a disputed point) that Valentinus was "born a Phrebonite" in the coastal region of Egypt, and received his Greek education in Alexandria, an important and metropolitan early center of Christianity. The word "Phrebonite" is otherwise unknown, but probably refers to the ancient town of Phragonis, near present-day Tidah. In Alexandria, Valentinus may have heard the Gnostic philosopher Basilides and certainly became conversant with Hellenistic Middle Platonism and the culture of Hellenized Jews like the great Alexandrian Jewish allegorist and philosopher Philo.