Richard Bauckham's thesis in "Jesus and the Eyewitnesses" is that names appearing in Mark's gospel identify living witnesses known to the community receiving the text. When Mark names Simon of Cyrene "the father of Alexander and Rufus," and Paul greets a "Rufus" in Rome (Rom. 16:13), this likely connects to the same family — confirming these are not invented characters but real people vouching for the account.