IIRC the Paulicians -- proto-Bogomils of Bulgaria, ancestors of the Cathars and Tondrakians -- used only two gospels as the entire scripture. They were a significant power in Anatolia until the 870s when their capital was destroyed by Basil I the Macedonian, Roman (Byzantine) Emperor. The religion decried the use of icons, as well as various earthly indulgences. It was Christian, but Gnostic-influenced.
A possible POD would be for a more successful Paulician movement that converts the Byzantine Empire. (There was a thread about just that
here.) We could have analogues of Cyril and Methodius that spread Paulician ideas in Europe. Eventually there could be a TTL reformation of sorts in which Catholicism or part of it is forcibly redefined to only recognize a few of the gospels.