When the New Testament canon was established there were over 100 "other" gospels considered in addition to the synoptic gospels of Matthew, Mark, Luke and the non-synoptic gospel of John. Top of the list of those that were considered but didn't make the final cut were the gospels of Thomas and Peter. Although in use by some Christian churches at the time, Third and Fourth Centuries, they didn't meet all the requirements that the Christian churches' greatest librarian and researcher, Eusebius, had determined were necessary. For a book to make the canon it needed to be traced directly to an apostolic source, was commonly in use, and all the major church bishops of the day were in agreement with their authenticity. 

A DevotionFor The Day