Of course there were other Christians. The Catholic church acknowledged their existence by ending it.
no there weren't....who would they have followed, these were the 12 hundreds...there were no bibles except those handwritten by the Catholic Church, and they were mostly in libraries....if you were not a Catholic you had probably never even heard of Christianity....there was no Christian "competition" at the time.....if you were Christian, you were Catholic. If you weren't Catholic, you were probably either Jewish or nothing