Paul was writing between the period of 50-60C.E.. The gospels of Mark, Matthew, Luke and John were not written till after Paul had died. The only accounts of Christianity during this period come from Paul. He never refers to Jesus as a literal human being who walked on the earth, which is strange to say the least. It seems that if someone called Jesus Christ (or of Nazareth etc.) had lived and walked on earth only a short while before Paul was writing, it seems that Paul didn't know about him. Paul never mentions Joseph or Mary, Bethlehem, Jesus' Baptism, Herod, the Census, Jesus going to Egypt, never quotes anything Jesus apparently said, doesn't reference any of the purported miracles Jesus performed, he never mentions that Jesus was ever a teacher, or that he had a ministry or had disciples. Paul doesn't mention the entrance into Jerusalem riding a donkey,
Doesn't that seem a little strange?
Paul only ever mentions three details of what we consider to be the 'Jesus story'. The Crucifixion, resurrection and ascension. Even then, Paul never mentions them in reference to being on earth, specifically in Israel. Paul's Jesus seemed to exist only in the spiritual realm, as he never writes about Jesus as ever existing as a human being on earth. This is an awfully dire situation to be in, considering Paul is the only link between the supposed life of Jesus, and the appearance of the first accounts of the life of Jesus.
EDIT: See comments below for the error I made (which has now been stuck-through). Pretty dumb mistake actually.