Development of the New Testament canon a heretic and in the early 4th century Bishop Theodoretus of Cyrrhus and Bishop Rabbula of Edessa (both in Syria) rooted out all copies they could find of the Diatessaron and replaced them with the four canonical Gospels (M 215). As a result, no early copies of the Diatessaron survive—although a very early fragment suggests it would have been crucial evidence for the true state of the early Gospels (see IX). By the 5th century, the Syriac Bible, called the Peshitta, was formalized, accepting Philemon, along with James, 1 Peter and 1 John, but excluding 2 John, 3 John, 2
Synoptic Gospels texts of the three synoptic gospels often agree very closely in wording and order, both in quotations and in narration. Most scholars ascribe this to "documentary dependence", direct or indirect, meaning the close agreements among synoptic gospels are due to one gospel's drawing from the text of another, or from some written source that another gospel also drew from. The synoptic problem hinges on several interrelated points of controversy: Furthermore, some theories try to explain the relation of the synoptic gospels to John; to non-canonical gospels such as Thomas, Peter, and Egerton; to the Didache; and to lost documents such