Heracleon

Heracleon was a Gnostic who flourished about AD 175, probably in the south of Italy. He is the author of the earliest known commentary on a book that would eventually be included in the Christian New Testament with his commentary on the Gospel of John, although only fragmentary quotes survive. He is described by Clement of Alexandria as the most esteemed (δοκιμώτατος) of the school of Valentinus; and, according to Origen, said to have been in personal contact (γνώριμος) with Valentinus himself. He is barely mentioned by Irenaeus (2.4.1) and by Tertullian. The common source of Philaster and Pseudo-Tertullian contained an article on Heracleon between those on Ptolemaeus and Secundus, and on Marcus and Colarbasus.