Notes on Non-anonymity . . . The book that I am referring to is Carson, D. A., and Douglas J. Moo. An Introduction to the New Testament. 2nd ed. Zondervan, 2005.
In the ancient world as in our world today, titles were used to identify works for which reference were made. There are many people who charge that the Gospel were in fact anonymous.
1. The Gospels were read out in church. When more than one was being read, it was necessary to tell the audience which Gospel was being read so that they could distinguish one from another.
2. During the 2nd century, the ascription of the titles of the 4 Gospels (e.g. “The Gospel according to Mark”, κατὰ Μᾶρκον εὐαγγέλιον) to the 4 Gospels works were unanimous. That is to say – wherever you found a Gospel work which started with “In the beginning was the Word, and the Word was with God…”, that work ALWAYS had the title “The Gospel according to John”.
Why is this important?
~ Suppose that the Gospels were originally anonymous, and that they later on came to acquire the titles that they now have. This means that for rough 60 years, they circulated anonymously, and then came to be called Matthew, Mark, etc. Here is the thing however. Had they indeed circulated all over the Graeco-Roman world (and beyond), and then suddenly acquired names 60 years later, then wouldn’t we expect to see some variation in the names – rather than unanimity?