What is Gnosticism?
Gnosticism is an ancient religious movement whose members claimed to have a secret knowledge of the means to salvation. The word comes from the Greek gnosis, meaning knowledge. Gnosticism flourished in the early Christian centuries. It borrowed ideas from Greek philosophy, pagan religions, Judaism, and Christianity. The movement was centered in Alexandria, Egypt, and its leaders included Basilides, Valentinus, and Marcion.
Gnostics believed in a supreme God, who was purely spiritual, and in a Demiurge, a lesser god who created the evil material world. They held that most men were entirely material and therefore doomed but that God sent the spiritual Christ to a few men, who possessed a divine spark, in order to save their souls through a gnosis, or revealed knowledge.
Some Gnostics were Christians, and there are some warnings in the New Testament against Gnostic beliefs. Such early Church Fathers as Irenaeus, Tertullian, Clement, and Origen denounced Gnosticism as a heresy.