As a child I was taught the traditional view that the four Gospels were written by disciples who were eyewitnesses of the events they spoke of. Yet the biblical scholarship of the 20th century argues that the evidence strongly suggests the authors of the Gospels were not eyewitnesses.
In a book commenting on the fact that the Roman Catholic Pontifical Biblical Commission changed its stance, rejecting the dogmatic position that the Gospels were written by eyewitnesses, Raymond Brown, a leading Catholic biblical scholar writes:
“The view that the evangelists were not themselves eyewitnesses of the public ministry of Jesus would be held in about 95% of contemporary [biblical] scholarship.
The designation that you find in your New Testament, such as “the Gospel According to Matthew” are the results of late-second-century scholarship attempting to identify the authors of works that had no identification. No evangelist indicated who he was.”