Wrong question. Read your history about Simon Magus. He did not [allegedly] take the reigns of the Church in Rome or anywhere during his lifetime, but he did leave behind a counterfeit Christianity with an ecclesiastical structure parallel to that of the Church there in Rome.
Several of the heresies of this counterfeit Christianity began to surface in the Church of Rome after the 4th century, including a leader playing a part "analogous to Christ", aka the Roman Pontiff or Vicarius Christi.
The true church didn't go along with this.
So where was the "true church" for 1500 years? (Or did the gates of hell prevail against it?)
-A8