Paul’s account of his encounter with the resurrected Jesus is very important to the story of Christianity, because the account of his experience with the “resurrected” Jesus in his letters are by far the earliest written account that we have of what and how people believed about the resurrected Jesus at the time, yet his telling of his story is still roughly 20 years after Jesus died. There are no earlier written records before that date that survived.
It is through the reading of his letters that we find out what was being transmitted and believed about Jesus around 50-55 CE (Common Era—the same as AD). We also have to remember that although his letters are included at the end of and after the Gospels of the New Testament, he is actually writing his letters to the Christian communities perhaps 15 to 20 years before the first Gospel (Mark) was written. Then another 15 or so years will pass before we get the next two Gospels (Mathew and Luke), and the last Gospel (John), and the second half of Luke’s Gospel (called Acts), comes yet another 10 or 20 years further beyond that (at the end of the first or the beginning of the second century).