By Bart D. Ehrman, The University of North Carolina, Chapel Hill
Christianity has always been astoundingly diverse. All the different factions are strikingly different in their beliefs and practices, yet all are Christian. Every Christian group of the 2nd and 3rd Christian centuries claimed that its views were correct and were the original views and that everyone else had a wrong view that was a perversion of the truth.

Differences in Opinion
Some Christians at the time to be sure said there was only one God, but some said there were two; some said 36 or 365; some said Christ was a human, but not God. Others said that he was God but not human; others said he was both God and human.
But even among these, there were wide differences. Is Christ 50% God and 50% human, or is he 100% of each or something else?
Some Christians said the world was created by the one true God. Others said it was created by an ignorant and arrogant secondary divinity. Others claimed it was created by a downright evil divinity. Look around the world—did a good God create this?
Some thought Matthew, Mark, Luke, and John were scripture. Others thought it was only one of them. Others thought it was none of them. Some thought the Gospel of Peter was scripture or the Gospel of Thomas or the Gospel of Truth, and so on.
The early Christianities had wildly different beliefs, practices, and written authorities. Scholars have emphasized this point since the mid-20th century and today it’s more widely known among the reading public at large, especially as people have become more familiar with other gospels that did not make it into the New Testament.
Diversity in the Letters of Paul
There is hard evidence of extensive diversity from the earliest days of Christianity. In fact, already in our earliest written Christian records, are the letters of Paul.
In his letter to the Galatians, Paul attacks Christian missionaries who claimed that pagan converts need to be circumcised and practice the way of Judaism to be true members of the Church. Paul doesn’t see this simply as an unnecessary step or as needlessly painful for the pagan men who converted.
Paul considers it a devilish scheme that runs completely contrary to his gospel. Anyone who follows the advice of these Judaizers, he says, is in danger of losing his or her salvation. Obviously, his opponents claimed the opposite. They said that their view was the original view, and that Paul was a heretical innovator.
And when you think about it, they may have been right. There were certainly followers of Jesus who held that view before Paul converted.
This article comes directly from content in the video series The Triumph of Christianity. Watch it now, on Wondrium.
Various Groups of Christianity
So, with all these disparate views, why didn’t Christians just read the New Testament to see whether they were right or wrong? The answer of course is that there wasn’t a New Testament.
Instead, there were lots of Christian groups with lots of Christian views claiming their views were the views of Jesus and the apostles and they had apostolic books allegedly written by Jesus’s own disciples to prove it.

The New Testament is the collection of books made by the winning party in the 4th century and later. If your scriptures were not Matthew, Mark, Luke, and John, but Thomas, Peter, Mary, and Philip, you would have a very different view of Christianity indeed.
Struggles Between the Christian Groups
Some form of Christianity certainly did overcome the pagan religions of Rome. The various earliest Christian groups were fighting various battles among themselves to hammer out what could be accepted as the true form of the faith and, at the same time, they were trying to win converts from paganism.
In this way of understanding the matter, there were struggles over what to believe and how to practice Christianity. One group won those struggles. That group became dominant. It took over Christianity and became the norm and called itself orthodox. That’s the view that eventually converted the empire.
Subsequent Orthodox View
One side won these debates, and the other groups either didn’t grow much at all afterward or almost completely died out. When Constantine converted, there was still a lot of internal diversity in early Christianity. But the major theological issues of the 2nd century had by that time been resolved.
The standard orthodox view believed there was one God, not two or more. He had created the world. Christ was his son, who is in some sense human and divine, who had existed before the world, and became incarnate as a human in it through a virgin. Christ’s death and resurrection brought salvation.
Anyone who became a follower of Jesus and joined his church would be given eternal life; anyone who did not would face eternal punishment. A kind of religion that was obviously a far cry from anything found in the traditional pagan religions of the empire.
Common Questions about Early Christianity
The early Christianities had wildly different beliefs, practices, and written authorities. All the different factions were strikingly different in their beliefs and practices, yet all were Christian.
Some early Christian groups said there was only one God, but some said there were two; some said 36 or 365; some said Christ was a human, but not God. Every group claimed that its views were correct and were the original views and that everyone else had a wrong view that was a perversion of the truth.
The standard orthodox view of Christianity believed there was one God, not two or more. He had created the world. Christ was his son, who is in some sense human and divine, who had existed before the world, and became incarnate as a human in it through a virgin. Christ’s death and resurrection brought salvation.