Christendom of today is a close version of what Constantine initiated in 325 a.d. It's not what Paul started, because Paul started nothing. It was the Christ who began the Christian Congregation, although not a religion, he called it "the one true faith". What religions claiming to be Christian are is Christendom. They're half pagan and half Christian. Even one part per billion pagan, makes them false religion. Christendom (all sects/denominations) is false religion. Christianity is the only true faith. Jesus taught no religion, and began no church or religion. Neither did Paul. Paul witnessed for Jesus for the balance of his life. Witnessing for Jesus is not "creating a religion".