TRADITION VS SCHOLARSHIP
The answer
Peter. An early bishop, Papias, called Mark "the interpreter of Peter," writing down what Peter preached. The letter written in Peter's name calls Mark "my son" (1 Peter 5:13).
Why it’s interesting
It's one of the oldest claims about how a Gospel came to be — memory passed from an apostle to a writer. How much weight to give Papias is a live scholarly question.
Genuinely debated
You can know the Bible.
Not just the stories, but the history, authorship, and scholarship behind it.