Following the death of Paul, Marcion took up the cause of Paul's teaching.  He lived late in the first century and was declared a heretic.

Why?  

For the same reason I was blackballed from a Christian social network, called Faithwriter. Because he wasn't teaching what was accepted by the Christian majority.  I was told that I could no longer contribute my writings,  because I was saying things that the traditional churches don't  teach.

Well, naturally I was, because I was introducing the obscure teachings of Paul.

No punishment for me, but Marcion was declared a heretic and shunned.

Marcion's cause for being declared a heretic was due to the fact, like Paul, he believed that there are two Gods..the god of this world and the supreme God of all..the same thing that I said, and more importantly, that's what Jesus said.

But even Marcion chose to ignore the tenets of Paul: We are justified not pardoned for our sins; All mankind will be "saved", eventually resurrected; the ecclesia is a part of the body of Jesus Christ, and their lot will be in the heavens.

 And so, as early as the first century, the orthodox churches ignored Paul's teachings, and took off in an entirely different direction. This, despite the fact that Paul was declared to be the apostle to the Gentiles, and the seat of the Christian Church in Rome, was a Gentile center.

How did this happen?

Because the early church leaders took the path of the Jewish followers of Jesus.. Even this was twisted, inspired by the god of this world, Satan, by incoroporating  certain time-honored pagan beliefs and celebratory days, to make "Christianity" more palatable.. introducing "heaven and hell", and "elevating' Jesus' family members to be  worshiped.. bobnPaul.