Mark, also known as John Mark, was the author of the second Gospel, the Gospel of Mark. Written in Greek for a Christian audience, and using terms that were meaningless to non-believers, Mark’s Gospel is a mixture of theology and history. It is written in a simple, forceful style. He was likely an eyewitness to the arrest of Jesus, as described in Mark 14:51-52.
Mark was likely too young to be an Apostle of Jesus, and probably simply accompanied his mother when she followed Jesus. See the Gospel of Mark for a discussion of how young Mark was.
Mark himself accompanied Paul and Barnabas, his cousin, on their missionary journey. Mark’s unexplained departure from that trip at Perga caused a later split between Paul and Barnabas, when Paul refused to take Mark on the second mission. Barnabas, in loyalty to his cousin Mark, broke off his relationship with Paul and traveled with Mark instead to Cyprus. Later Paul realized he was wrong about Mark and requested him to come visit. Mark and Paul were reunited and went on an additional trip together.
Mark was close to the Apostle Peter, who once described Mark as "my son.". According to Papias, Mark was the interpreter for Peter and the Gospel According to Mark is often considered to be Peter’s Gospel as transcribed by Mark. In Acts 12:12 when Peter escapes from prison, he goes to the home of Mark's mother, which was then the center of the Church. If Mark 14:51-52 is truly a self-description of Mark as a young man, which some scholars believe, then the Last Supper (Mark 14:22-25) was also held in the home of Mark's mother.
Mark has been the patron saint of Venice ever since the Venetians led a successful mission to recover his body from the Muslims in Alexandria, and to this day his body lies in St Mark's Basilica in the city. Depictions of Mark are common in Venetian art, and often feature a lion, the animal that is identified with him.
The Christian Coptic Orthodox Church of Egypt reveres Mark (Saint Mark, or Mark the Evangelist) as its first Pope (Bishop of Alexandria).