History of Gnosticism

 

As Rome spread many cultures and beliefs mingled.  Because of the violence there was a renaissance of spiritual thought and many Christian Sects developed.
By 325AD, Constantine brought these leaders together to develop one Church system in order to unify his Empire.  The Gnostic beliefs of understanding God from within was buried by the Roman Church/State's rule that God could only be understood through the Church.

For a complete understanding....
Gnostic Christianity and history http://www.essene.com/Gospels/GnosticAndSophia.html