Koran

According to wiki the Koran states that Jesus was a true prophet but his message was lost, and the Christians are following a cobbled-together facsimile.

Which is why God sent Mohammed, to fix up the mess. He did a great job eh?

You could blame them both for the chaos they have created. However without the internet or even the printing press it was a tough gig, to say the least.

It is very likely that one of the prophets got it wrong. Probably both. History doesn’t record whether either of these gentlemen was truly mad and believed the prophet of God business