Marcion was one of the most significant and, in a way, perplexing figures of the second century CE—significant both for founding the Marcionite Church and for providing the stimulus for the formation of the New Testament canon, and perplexing because of the difficulty of classifying him among contemporary thinkers. He is often called a Gnostic, and there are certainly distinct affinities with Gnosticism in his cosmology and soteriology; but his lack of a mythical anthropology and of any syncretistic tendency sets him apart.

A native of Sinope in Pontus, he was born c. 85 and must have died c. 159, since there is no suggestion in our sources that he survived until the reign of the emperor Marcus Aurelius (161–180). According to the ecclesiastical writer Hippolytus, Marcion was the son of a bishop, and indeed there are indications that he grew up within the...