Matthew the tax official

Matthew was a tax official from Galilee who had been one of Jesus' original disciples. Luke the physician, Mark of Jerusalem and he wrote accounts of the life of Christ. These accounts differed somewhat, because of a phenomenon the First Doctor called "Chinese whispers". Moreover, Matthew's account came before the others, like the gospel of Mark, which were said to have been "based on" Matthew's version. (PDA: Byzantium!)

Behind the scenes
Byzantium! doesn't give its readers much in the way of identification for this individual. He's never described as "Saint Matthew", because, of course, the setting for this book is before the practical founding of the Catholic Church. He is therefore only given a descriptive name of "a Galilean tax official known as Matthew".