oracle said:
Hmmm. It would be interesting to know everything that went on during those times. From what I've read, Christianity was very diverse and disunified. There were also many forgeries at the time, so the attempt of the orthodoxy was to keep Christianity genuine,to unify, the canon was created and so on. However schisms were already beginning early in christianity that is why it became so diverse. I don't believe that Christianity today is near it's original form.
There's a good deal of truth in what you say. I do disagree with that last sentance, but that's a whole 'nuther subject
.
The canon was indeed created in response to the canons of other groups. Marcion, a rather potent Gnostic teacher of the second century, had his own Bible, for instance. It took several hundred years for the process to finish, and when it did, Gnosticism was already gone.
For the Gnostics, you have several documents such as the Nag Hammadi manuscripts. This site will help with their side some
http://www.gnosis.org/naghamm/nhl.html. Due to the nature of history,though, most of their side has been lost. The Gospel of Thomas is another good source for Gnosticism.
The problem with Gnosticism here, though, is that it is very difficult to quantify. One group believed one thing, and another another.
For the Orthodox side, I would say look to St. Irenaeus. He's the most relevant to the discussion. The epistles of I-III John in the New Testament are probably written against Gnostics. I also firmly believe that the Apostle John had Gnostics in mind when he composed his Gospel. So, those two are good sources. For St. Irenaeus, go to
http://www.ccel.org/fathers2/ and read
Against Heresies. It's long and boring, but you can see how the Orthodox Christians responded at the time, and you can see how they argued their cases.
That's the best I can give you for being able to look at both sides.
My interpretation on the Gnostics is obvious, and I think the original branch started by the Apostles survived and still does. As I said, though, that's another thread.