“Marcus, my son, saluteth you.” Mark, the follower of Peter, while Peter publicly preached the Gospel at Rome before some of Cæsar’s equites, and adduced many testimonies to Christ, in order that thereby they might be able to commit to memory what was spoken, of what was spoken by Peter, wrote entirely what is called the Gospel according to Mark. As Luke also may be recognised by the style, both to have composed the Acts of the Apostles, and to have translated Paul’s Epistle to the Hebrews.
Jude, who wrote the Catholic Epistle, the brother of the sons of Joseph, and very religious, whilst knowing the near relationship of the Lord, yet did not say that he himself was His brother.
Clement of Alexandria
The Stromata, Book VIII
Chapter VIII