The reality is that we know very little about author of the Gospel of Mark.
As Jesus passed on from there, he saw a man named Matthew sitting at the customs post. He said to him, “Follow me.” And he got up and followed him.
The author of the Fourth Gospel is generally considered to be St. John. The three Letters of John and the Revelation of John are also attributed to this saint.
St. Luke, or Luke the Evangelist, was the most prolific of the Gospel writers.
Now on the occasion of the feast [Pilate] used to release to them one prisoner whom they requested.