Matthew the tax official

Matthew was a tax official from Galilee who had been one of Jesus' original disciples. He, Luke the physician and Mark of Jerusalem 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, as he was the only one of the three to have actually been in contact with Jesus. (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".