Indeed, many of the stories of Jesus in the Gospels are myths. For instance, his birth of a virgin, the resurrection of Lazarus, his walking on the waters, and many of the dialogues (in the Fourth Gospel) are not historical. However, Jesus had to exist, as Caleb pointed out. But he was a Jew, a leader of a sect, so I strongly doubt (as many scholars do) that he sent his disciples to preach and baptise people of all nations in the name of the Father and the Son, and the holy spirit.
In conclusion, I believe that only a ten percent of what we read in the Gospels is historical.