The traditional master narrative about the origin of the New Testament Gospels states that the Apostles and other Christians
passed on their memories of Jesus and his words and actions. As the generation of Jesus’ direct disciples aged, the evangelists collected the most important of Jesus’ words and actions in Galilee, and the narratives about the events in Jerusalem leading up to the crucifixion, and wrote them down to preserve them for Christian teaching and mission.
In my opinion, the Gospels and the Acts of the Apostles should be evaluated like historical novels about Jesus and the Apostles. They include much historical material, but are designed according to literary criteria in which the beauty of the narrative is an important factor.