The writings of the church fathers are referred to as "the tradition" or as "patristic sources" in most discussions of this subject. All information from after this time either depends on earlier available sources or is suspect because we are unable to determine what the earlier sources are.
This article is by no means exhaustive on the subject but addresses some of the most common questions concerning the New Testament. But that said, there are certain books, such as Romans, Corinthians, and Galatians, for which virtually no one would dispute an A. To evaluate the accuracy of our New Testament, we have to look at two factors.
For further study we recommend “The Canon of Scripture” by F. Bruce (Inter Varsity Press.) Here’s an important fact to keep in mind: Jesus died in roughly A. One factor is the number of ancient manuscripts (copies of the original) we possess, and the second is the time gap between when the original document was written and when the earliest surviving copies were written.
The earliest New Testament books, the letters written by Paul, were composed in the decade of the 50s.
In the mid-60s, James, Peter, and Paul are all killed.