The Gospel was revealed to the apostle Paul, Galatians 1:11-12. And was preached by Peter on the day of Pentecost when 8,000 Jews became Christians, Acts chapter 2. Matthew, Mark, Luke and John are not the Gospel. The Gospel is the work that Jesus did in our name and on our behalf that justifies the ungodly, Romans 4:5 and reconciles us and the world unto God, 2 Corinthians 5:18-19.The Catholic Church wrote the Gospel. The writers of the New Testament were all Catholic. There was no other Christian religion until 1054 A.D., when the Orthodox splintered off. They retained Apostolic Succession, however, and, therefore, all seven Sacraments. Protestantism didn't start till way late in the game, the 16th century. And it has continually splintered every since. The Gospels were not written in the 16th century.