St. Mark the Evangelist
While still young, Mark went with the two great saints, Paul and Barnabas, as missionaries to bring the teachings of Jesus to Cyprus and other new lands. Before the journey was over, though, Mark had an argument with St. Paul and immediately returned to Jerusalem. Paul and Mark later made peace with each other. In fact, Paul wrote from prison in Rome that Mark came to cheer and help him.
Mark also became a beloved disciple and was like a son to St. Peter, the first pope. St. Mark was made a bishop and sent to Alexandria, Egypt. There many people who heard him preach became Christians. He worked hard to spread love for Jesus and his Church and founded the first famous Christian school in Alexandria.
He went through long and painful sufferings before he died a martyr for his faith. St. Mark's relics were brought to Venice, Italy. He is the patron saint of that famous city. People go to the beautiful basilica of St. Mark to honor him and to pray to him.
Reflection: "Go into all the world and preach the gospel to the whole creation." (Mark 16:15)
Source: http://www.holyspiritinteractive.net/kids/saints/0425.asp