The Acts of Apostles (12:12) mention a man named John Mark in connection with a house that served the Christians in Jerusalem as a place for gatherings. It was perhaps his cousin Barnabas (Col 4:10) who acquainted him with Paul and Mark accompanied both of them on the first missionary journey (Acts 12:25). Eventually he split away and returned to Jerusalem (Acts 13:13), which also caused tensions between Paul and Barnabas (Acts 15:37).
This Mark is attributed the authorship of Mark’s gospel (the gospel actually never mentions the author), which is commonly dated about 65-70 AD (the first of the first canonical gospels).
Not much verifiable information is known about Mark, but tradition has him as the founder of the Church in Alexandria, where he also suffered martyrdom. His relics (according to a tradition) were transferred to Venice (Italy) and also to the island Reichenau (in Lake Constance in southern Germany).
Mark’s attribute as the evangelist is a lion.