Mark the Evangelist was a very important person in the Bible. He was one of the people who wrote down stories about Jesus and helped spread the word about him.
Now, Mark was also known as John Mark and he was a follower of Jesus. He helped the apostles (Jesus' closest friends) with their mission to tell people about Jesus. Mark saw many amazing things that Jesus did, like healing sick people and performing miracles.
Mark wrote one of the books in the Bible, called "The Gospel According to Mark". It's all about Jesus and his life. Mark wrote down stories that he had heard or learned from other people, so we know a lot about Jesus today because of his book.
Mark was always traveling and spreading the word about Jesus. He even traveled with the apostle Paul on some of his journeys. Mark was a very important person because he helped keep Jesus' teachings alive for many years, and even now, his book is still read and studied by many people around the world.