According to Acts, Simon was a Samaritan magus or religious figure of the 1st century AD and a convert to Christianity, baptised by Philip the Evangelist. Simon later clashed with Peter. Accounts of Simon by writers of the second century exist, but are not considered verifiable. Surviving traditions about Simon appear in orthodox texts, such as those of Irenaeus, Justin Martyr, Hippolytus, and Epiphanius, where he is often described as the founder of Gnosticism, which has been accepted by some modern scholars, while others reject that he was a Gnostic, just designated as one by the Church Fathers.
Justin, who was himself a 2nd-century native of Samaria, wrote that nearly all the Samaritans in his time were adherents of a certain Simon of Gitta, a village not far from Flavia Neapolis. According to Josephus, Gitta (also spelled Getta) was settled by the tribe of Dan. Irenaeus held him as being the founder of the sect of the Simonians. Hippolytus quotes from a work he attributes to Simon or his followers the Simonians, Apophasis Megale, or Great Declaration. According to the early church heresiologists, Simon is also supposed to have written several lost treatises, two of which bear the titles The Four Quarters of the World and The Sermons of the Refuter.
In apocryphal works including the Acts of Peter, Pseudo-Clementines, and the Epistle of the Apostles, Simon also appears as a formidable sorcerer with the ability to levitate and fly at will. He is sometimes referred to as “the Bad Samaritan” due to his malevolent character. The Apostolic Constitutions also accuses him of “lawlessness” (antinomianism).