The beginning of the gospel of Jesus Christ [the Son of God]. (Mark 1:1)
https://bible.usccb.org/bible/readings/042523.cfm
Why write a gospel? That’s the question the church celebrates today in this feast of the gospel writer, which we call Mark. “According to Mark” is the name the church puts on the shortest of three synoptic gospels (Matthew, Mark, Luke-Acts). Although all four gospels were anonymous (we don’t actually know who wrote them since the writers didn’t put their names on them), the church much later put names on them associating them with names of persons mentioned in the Scriptures. What we celebrate today is not so much a person, rather the gospel itself. The “beginning” of the gospel is when we too share the Good News of Jesus Christ [the Son of God] with others, thus becoming the “living gospel for all people to hear.”