The Gospel of Barnabas
The Gospel of Thomas
Deceptions and Myths of the Bible - Lloyd M. Graham
The Bible itself (most people read the King James version)
any World Civilizations book that covers the early development of religions

Thanks for making me look up my resources cause I just found a better date (more inline with the one you mentioned) for the Nicean Council at 325 CE.
Thanks for reading. I love you.

In Rotation:
Tool - Aenema
Deftones - White Pony
A Perfect Circle - Mer De Noms
Down - Nola
Slum Village - Fantastic Vol II
Black Sabbath - Sabotage