Gnosticism has been around since before the birth of Christ. It had a tremendous influence on the early church, the canonization of the New Testament, and continues today to influence the understanding of Christianity. Many consider the growth of the American religions to be a distinctive form of Gnosticism. I will start with a broad definition of Gnosticism.
GNOSTICISM is a mixed and diverse group of thinkers, ideas, and treatises that became a force in the second century CE and continued to exert an important influence on ancient religion into the fourth century. While the most recent scholarship has tended to emphasize pagan and Jewish, as well as Christian, forms of Gnosticism (beginning in the first century), the major gnostic impact was made on the doctrine and structures of the Christian church in the second and early third centuries. Its critics, both Christian and Pagan, seem to have regarded it primarily as a Christian heresy. .
In addition to numerous scattered groups, two main schools of systematic gnostic thought seem to have existed in the second century the Basilideans and the Valentinians, the latter divided into Eastern and Western branches. In addition, Marcion, a radical exegete of Paul tinged with gnostic assumptions, founded a group and made the first attempt to create a closed canon of the New Testament. Marcion and the Western Valentinians appear to have been the most feared by catholic theologians. Until recently, our knowledge of gnostic thought was almost exclusively dependent upon the reports of its critics (e.g., Irenaeus, Hippolytus, Tenullian, Origen, Plotinus); but a cache of documents found at Nag Hammadi in Egypt in 1945 has provided originals of some treatises alluded to by those critics and has enabled scholars to see how much more widespread and diverse Gnosticism was than previously imagined. .
At the heart of the gnostic concern was the revelation of the hidden Gnosis (Greek meaning "knowledge"), the possession of which would free one from the fragmentary and illusory (or evil) material world (bodily existence) and teach one about the origins of the spiritual world to which the gnostic belonged by nature.