The Koran and Christian Apocrypha

I’m finally getting around to something that I’ve always wanted to do for academic purposes, that is read the Koran. If you read the last First Things issue, there was a great article on heretical Christian documents being employed in the construction of the Koran.

I’ve recently learned that the Koran seems to refer to the following heretical Christian apocryphal books:

• Proto-Evangelion of James
• Infancy Gospel of Thomas
• Gospel of Pseudo-Matthew
• Arabic Infancy Gospel
• Taitian’s Syriac Diatessaron (blend of the four Gospels) may also be a source

I can’t remember who it was (maybe St John Damascene?) who said that Muhammad composed the Koran with the help of an Arian monk. Has anyone ever heard of this tradition?