New Testament document, in addition to some other sources, to write their individual gospel accounts. These three gospels are called the Synoptic gospels because they include many of the same stories, often in the same sequence, and sometimes exactly the same wording. Scholars agree that the Gospel of John was written last, by using a different tradition and body of testimony. In addition, most scholars agree that the author of Luke wrote the Acts of the Apostles. Scholars hold that these books constituted two halves of a single work, Luke-Acts. Strictly speaking, each gospel and the book of Acts is arguably anonymous.
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