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
New Testament Writings attributed to the apostles circulated among the earliest Christian communities and the Pauline epistles were circulating, perhaps in collected forms, by the end of the 1st century AD. One of the earliest attempts at solidifying a canon was made by Marcion, "circa" 140 AD, who accepted only a modified version of Luke (the Gospel of Marcion) and ten of Paul's letters, while rejecting the Old Testament entirely. His canon was increasingly rejected by other groups of Christians, notably the proto-orthodox Christians, as was his theology, Marcionism. Adolf Harnack in "Origin of the New Testament" (1914) observed that the church