Because the 'winners' get to write the story, we can only guess, well - guess about some stuff concerning the creation of the New Testament that we know today. There is evidence, often overlooked as in the quote I provided from Justin Martyr's
Dialogue with Trypho which would appear to show that Justin held some beliefs from the Marcionite faith, even though Justin's writings are often used to provide support for presently-accepted beliefs.
One recent commenter posted that the "canon was settled by the end of the 1st century", yet one of those websites I bother to read has the following about the canon.
History of the Bible
The assemblage of the New Testament is a very interesting process and a highly complex one. It can, however, by summarized relatively simply as follows.
Various Christians wrote books explaining the history of the Christian Church (including Gospels about the life of Christ and more general histories such as the Acts of the Apostles) and letters addressed to specific communities and persons (such as the letters of Saint Paul) and also what are best considered to be “open letters” (such as Hebrews). There were hundreds of different documents circulating around, all of them purporting to the authentic Christian teaching and accurate history and doctrine.
However, many of these documents were not what they claimed to be – they were forgeries not written by the people whose names they bore, or were heretical documents advancing novel notions about Christ. Some of these documents have survived today – examples are the Gospel of Judas and the Gospel of Thomas. Neither of these documents were written by their alleged authors – they are late forgeries designed to cash in on the success and popularity of Christianity.
Out of all these hundreds of documents – many of them forgeries – the current 27 book New Testament appeared.
This process took a long time – roughly 300 years went by from the writing of the last book of the New Testament (Revelation) until the list was finalized.
Examples from early leaders of the church:
Irenaeus (c.130-c.202) in
Adversus Haereses chose only 20 books for his 'accepted' texts: Matthew, Mark, Luke, John, Acts, Romans, First Corinthians, Second Corinthians, Galatians Ephesians, Philippians, Colossians, First Thessalonians, Second Thessalonians, First Timothy, Second Timothy, Titus, Philemon, First John, and Revelation
Tertullian (155-220) didn't like Hebrews, First Peter, Second John, Jude, and the Shepherd of Hermas. The Shepherd is found in the Codex Sinaiticus which is dated to the mid 4th century. Obviously not every scribe listened to Tertullian.
Clement of Alexandria (150-215) saw the epistles to the Hebrews, Second John, Jude, First and Second Epistles of Clement (of Rome), Epistle of Barnabas, Shepherd of Hermas, and Revelation of Peter, as holding matters of interest but he didn't view them as 'scriptural' or canonical.
As with all of the early writings, today we often only have quotes attributed to the early church fathers by those who were writing centuries later.
Ten fragmentary texts of New Testament books which are dated to the 2nd century are the oldest ones known of at this time. None of them have the title that we associate with the words that can be read. Some academic types speculate that the passages found in these fragments may be the source for the books we know but that they were actually pulled together by those scribes who wrote the full texts without attribution to the original author.
