\b0 This terms refers to a system of spiritual doctrines from the Hellenistic-Roman period which flou
rished along side ancient Christianity.\par
The constituting element of the system is knowledge (\i gnosi\i0 ) on which spiritual salvation depends. The knowledge, however, is not of the type that is derived from experience or uncovers reality by advanc
ing from principles or theories. Rather, it is a revealed knowledge of divine mysteries which is attained in a mysterious way and is available only to a small privileged group. \par
For the Church in the early centuries of Christianity, Gnosticism pos
ed its greatest threat. Its practitioners included Simon Mago, Basilide of Alexandria, and Carpocrates of Epiphane. In Rome, the doctrine was taught by Valentino, as well as Marcione, and his school. \par