2. Whence he is called Mark. He is not John Mark, of whom mention is made in Acts 12:12.
Therefore, although a Jew, and indeed a ἑβραΐζων/Hebrew-speaking rather than a ἑλληνίζων/Greek-speaking one, and also a Jerusalemite, as not a few gather out of Acts 12:12 (concerning which afterwards); by the ancients he is called by the Roman name of Mark.But the learned think that he had a Hebrew name, not differing completely from that Latin name, and that he afterwards exchanged it with the Latin.Thus Job, the Brother of Onias, was called Jason; Saul was called Paul.And today those having the name Mordecai are called Mark.Whatever the case may be, it is likely that he was given the Hebrew name first, but that afterwards the foreign name of Mark stuck to him.But whether he was first named John, and so he is the same that in Acts 12:12 is called Ἰωάννης ἐπικαλούμενος Μάρκος, John surnamed Mark, Son of Mary, whom in the same passage, verse 25, Barnabas and Paul are found to have joined with themselves as an associate of the preaching office, as the Most Learned Kirstenius, and others not a few think, is not clearly proven.That the Most Learned Grotius calls into doubt by these arguments:that the ancients consistently call this writer Mark, never John:and that they join him to Saint Peter as an associate and disciple in such a way that not only of Barnabas, but also of Paul, whom that John Mark followed after the disagreement arose, they make no mention.Hence also in the Roman Martyrology mention is made of the Evangelist Mark on April 25, but John Mark, as diverse, on September 27.Therefore, we prefer rather to leave a matter thus doubtful undecided, than rashly to determine anything.
 Jason succeeded his brother, Onias III, as High Priest in Jerusalem (175-171 BC), during the reign of Antiochus Epiphanes. Jason was a Hellenist.  See Acts 13:9.  See Acts 15:37-40.  The Roman Martyrology was published in 1583 under Pope Gregory XIII. It is the official martyrology of the Roman Church.