Of these Gospels, again, that of John ranks as the latest. It presupposes the others, and shows such a dogmatic tendency, that it cannot be considered the source of the story. Of the remaining Gospels, which on account of their similarity as to form and matter have been termed "Synoptic" (i.e., such as must be dealt with in connection with each other and thus only give a real idea of the Saviour's personality), that of Mark is generally regarded as the oldest. Matthew and Luke rely on Mark, and all three, according to the prevailing view, are indebted to a common Aramaic source, wherein Jesus' didactic sermons are supposed to have been contained. Tradition points to John Mark, the nephew of Barnabas, pupil of Peter, and Paul's companion on his first missionary journey and later a sharer in the captivity at Rome, as the author of the Gospel of Mark. It is believed that this was written shortly after the destruction of Jerusalem (70)--i.e., at least forty years after Jesus' death (!). This tradition depends upon a note of the Church historian Eusebius (d. about 340 A.D.), according to which Papias, Bishop of Hierapolis in Asia Minor, learnt from the "elder John" that Mark had set forth what he had heard from Peter, and what this latter had in turn heard from the "Lord." On account of its indirect nature and of Eusebius' notorious unreliability this note is not a very trustworthy one, [375] and belief in it should disappear in view of the fact that the author of the Gospel of Mark had no idea of the spot where Jesus is supposed to have lived. And yet Mark is supposed to have been born in Jerusalem and to have been a missionary! As Wernle shows in his work, "Die Quellen des Lebens Jesu," Mark stands quite far from the life of Jesus both in time and place(!); indeed, he has no clear idea of Jesus' doings and course of life. [376] And Wrede confirms this in his work, "Das Messias-geheimnis" (1901), probably the clearest and deepest inquiry into the fundamental problem of the Gospel of Mark which we possess. Jesus is for Mark at once the Messiah and the Son of God. "Faith in this dogma must be aroused, it must be established and defended. The whole Gospel is a defence. Mark wishes to lead all his readers, among whom he counts the Heathens and Gentile Christians, to the recognition of what the heathen centurion said, 'Truly this man was the Son of God!' [377] The whole account is directed to this end." [378]