I don't believe it is Christianity that has gone wrong, but that it is mankind that has always been wrong since the Fall. Christ started His church and never called it by a denominational name. That was man's idea, because man thinks he knows better than God.
Christ started the true Christian church (no denomination) and expected believers to adhere to the Christian beliefs that He instituted. Unfortunately man in his own "wisdom" said, "What the Bible says can't be true nor all of the truth. I know there is more." Then man proceeded to change God's word into what he wanted it to say--thus, dozens of translations, versions, and perversions of the holy scriptures. Of course, there had to be more and more denominations that reflected what man chose to believe--regardless of what God said.
I'm not aware that the Catholic religion was ever correct in their theology and teachings. They persecuted and even killed Christians, and to this day they believe that THEY are Christians. Many other false religions claim to be Christian while denying the deity of Christ, the virgin birth, the Trinity, and adding to and taking from the scriptures.