I have noticed recently that many people seem to have genuine questions about Christianity: Did Jesus really exist? Who founded Christianity? Was John the Baptist an Essene? Was Jesus an Essene? Why was there not more written about Jesus, the miracle worker, by non-Christians? Did Josephus write about Jesus? Was Paul the true founder of Christianity? All are good questions!
Let's look at the last question first about Paul being the true founder of Christianity. Although Paul has a very dominant place in the New Testament, he could not have invented Christianity. The book of Acts (written by Luke, who was a physician and a companion of Paul on much of his travels) indicates that the early church first gathered around the preaching of Peter and the other apostles several years before Paul entered the scene in Jerusalem.
The earliest followers of Christ, who were all Jews, saw Jesus, primarily as the promised Messiah of the Jews, who had risen from the dead. Although "Acts" was written by Paul's companion, Luke, Paul most certainly did not dictate to Luke what to write. The early sermons by Peter do not reflect Paul's theology, but practiced a simple approach to faith, "Repent and be baptized." Furthermore, the initial movement of followers of Jesus, the Messiah, had been well underway for several years by the time Paul had his dramatic moment when he was blinded by a great light from Heaven and heard the voice from Jesus speaking to him.
Some skeptics might think Paul made up the whole incident of his conversion to give his conversion validity. However, if one looks at Paul's life, there was no good reason for him to become a convert without something significant and powerful happening. Paul, who formerly went by Saul, was an up and coming, very ambitious Pharisee. He was a student of Gamaliel, one of the most revered of the Pharisees. Saul hated the followers of Jesus. considering them as heretics. He was on his way to arrest Christians in Damascus and put them in prison or do worse, when his conversion happened.
Paul was present and approving of the stoning of Stephen, who was the first Christian martyr. He had nothing to gain by becoming a follower of Jesus. Instead, he was giving up a great future, plus he was risking his life. He had to have known quite well that he would be hated in Jerusalem by the top Jews and in danger of being arrested and killed if he returned to Jerusalem as a follower of Jesus. He would have had no idea he would ever become famous. In fact, the fame that he has now was never that great in his life-time.
Furthermore, Paul was never a top leader of the Church. He was a leader, but no more important than other apostles such as Peter, John, and Apollos, who were basically missionaries. The top leader of the Church in Jerusalem, and thus the recognized leader of all of the followers of Jesus Christ, was the brother of Jesus, James (not the James who was the brother of John), a leader whom Paul respected and to whom he looked for guidance and approval.
After several missionary journeys, but right before he traveled to Rome, Paul first went to Jerusalem to observe the Jewish feast of Pentecost. He was himself under a Jewish vow and needed to got to the temple to properly end it. James directed Paul to go to the temple with some other Jewish believers to end their vows together to let non-Christian Jews know that Paul was still a faithful Jew. Paul readily acquiesced. Unfortunately, this plan back-fired, because some Jews who had seen Paul in the city in the company of non-Jewish Greeks, thought he had taken the Greeks into the temple, and they started a riot. It was because of the riot and the efforts by Jewish leaders to punish, even kill Paul that he appealed to Caesar, because he was a Roman citizen.
Another piece of evidence that Paul did not create Christianity is found in the writings of the early Christians in the late first century and the second century. They are not very far removed in time from the early days of the faith. What is interesting to me is how little their theology reflects Paul's teachings about being by grace and not by works. In fact, Paul is barely mentioned in these writings. Baptism seemed to have been the central entry into the faith and was preceded by a day of fasting. Some of the leaders taught quite strongly that if someone sinned seriously after being baptized, there was either no hope for redemption or only one chance at repentance. That is not Pauline theology or John's theology. My point again is that Paul's teachings did not make as great an impression on all of the church at that time as people today think he did. He had written to specific churches and these letters had not gotten around to all the churches. Paul is extremely well known today, mainly because of his writings, which were brilliant, and over the years have grown in their influence.
Be open minded and read the New Testament book, "The Acts of the Apostles" (often called "Acts"), which follows the book of John in the New Testament. It is a fascinating account of the early church before Paul and much about Paul's adventures and the people he met on his journeys. Also, the first two chapters of Paul's letter to the Galatians give an account, not in the book of Acts, of how Paul spent his very early days as a new convert, including a revelation by Jesus Christ himself.
Here are some books to read that will show what the early church in the late first century /early second century was really like: "The Early Christian Fathers" subtitle, "Writings of the Early Fathers," edited and translated by Henry Bettenson, and "The Early Christians, After the Death of the Apostles," by Eberhard Arnold, founder of the Bruderhoff, a Christian community movement, still going strong.
Very interesting, Marjorie, and remarkably detailed.
I think some scholars term Paul the "inventor" of Christianity, in the sense of it becoming a Gentile movement that seemed distinctly different from the earlier Christianity that retained its Jewish character.
Paul, in a sense, did reframe Christianity to make it more understandable to Gentiles. He also was led in declaring that Gentiles did not have to become Jews and follow Jewish rules in order to become Christians. He was quite fierce in that, as we see in Galatians 5, "Stand fast in liberty," preceding a discussion of Christians and the rite of circumcision.
This of course merely adds to what you have outlined. While there are many Christian denominations, there is really only one Christianity, persons who declare themselves as followers of Jesus.