This contribution aims at closing the discussion on the literary origin of the Faust character, as it already appears in the Faustbuch (1557). Beyond historical or pseudo-historical traits (in so far as a Johannes Faust did exist, which ever may have been his real name), it seems that most of the legend was built on the confusion of different characters: one, historical as well, i.e. the Pope Alexander VI Borgia; two others semi-legendary, i.e. the Iranian sorcerer Zoroaster and most of all the ancestor of Gnosticism Simon known as Simon the Sorcerer. We follow the steps of the confusion concerning Simon and Doctor Faust through various literary testimonies and we have evidence to assert that its origin is to be sought in the Clementine tra...