If Matthew, Mark and Luke were creating a Messiah from scratch, or, more probably, recording the invention of believers who went before them, then it is unlikely they would have arrived at the loser preserved in their accounts. The Jesus we find there is nothing like the Messiah anticipated in Jewish scripture nor by Jews at the time.
He is a false prophet, his good news about the imminent arrival of the Son of Man and the Kingdom of God being patently unfulfilled. His ministry is a failure, ending as it does in ignoble execution. This is not the Messiah anyone would create if they were inventing one to satisfy the longings of a thwarted people. In particular, God’s emissary would not lose control of the situation in the way the Jesus of the synoptic gospels does. He would not allow himself to be executed by the occupying forces in the manner the gospels record. (All the surviving sources attest to his death by crucifixion; we can be fairly certain he died in this way.)
A created Messiah, on the other hand, would surely have announced the arrival of the Son of Man/Kingdom of God before leaving the stage of his own volition – ascending to heaven perhaps as some of the gospel writers eventually have him do – to await the unfolding of the events he had proclaimed. Of course, the death of a godman is a recurrent theme in the mythologies of the ancient world, so it is possible that an unpleasant death would be invented for an imaginary Jesus so that he complied with the trope. But, as I’ve already suggested, the central figure of the synoptic gospels is noticeably ungodmanlike. We only see him as such through the distorting prism of Paul’s theology; without this, we can see that the gospels of Mark, Matthew and Luke really don’t portray him like this at all.
It seems much more likely, therefore, that what the synoptic writers are conveying are distorted memories of an individual who actually lived. A man who promised much but whose mission went drastically wrong but which would, his earliest followers believed, be completed by God himself in the near future. This latter part is, as we now know, pure invention, the gospels conveying only an imaginative interpretation of this man. It would seem, nonetheless, to be an interpretation of someone – a charismatic Jewish preacher and failed heir-presumptive – who had actually lived some years before.
As I said at the beginning of this two-part post, I don’t really care whether Jesus existed or not. The end result is the same; millions of people seduced by a significance he did not have, either as a real person or as an imaginary construct. On balance, for the reasons I’ve touched on in these posts, it seems to me Jesus – Yeshua bar Yosef – did once exist. Like we all must, he died and others set about interpreting his life in their various, incompatible ways. These interpetations are all ultimately meaningless; we can be absolutely certain that, whatever the Bible and Christians today tell us, Jesus, whether he lived two thousand years ago or not, does not exist now in any shape or ethereal form.