Which Christians religion was the first one?

Answer 1

We are not really sure which Christian sect was first. Many scholars say that Paul's Christianity was quite different to that taught by the Jerusalem Church led by James and Peter, thus we have Paul (in Galatians) explaining to the Jerusalem brethren the gospel he taught. Paul also complained of those who taught a "different Christ", thus another form of Christianity. All this within ten to twenty years of the traditional year of the crucifixion.

Some scholars say that the Christianity that we have today began with the writing of the New Testament gospels, the first of which, Mark, was written around 70 CE. Others believe that the Gnostic Christians, who are known to have been important during the second century, may have been among the very earliest Christians.

The Markan Christians (A term I would use if indeed the dominant sect began after the authorship of Mark's Gospel) eventually splintered, with first the Coptics separating, and the Great Schism of 1054 creating the separated Roman Catholic and Eastern Orthodox Churches. The Catholic Church was splintered in turn, with the Protestant Churches beginning to form during the period known as the Reformation.