The year 220? Thanks, I stand corrected, but that still doesn't invalidate my proposition that the keys were an invention to prove a point that they already held to be true.
The problem is that I don't believe in secret teachings or evolutionary doctrine.
You mentioned the Trinity as evolutionary doctrine, but that is terminology. Nothing has been added to the Scriptures regarding the Father, the Son, and the Holy Spirit. We just use a different name.
Regarding the keys given to Peter (only mentioned in 1 of the 3 tellings of the story) their meaning has been a theological evolution. Something has been added to Scripture, not just restated.
The same evolutionary doctrine can be seen in the beliefs about Mary. I don't know if she was a perpetual virgin, but I know belief either way is not a condition of salvation.
Beleif that Jesus was born of the virgin Mary is found in every creed. Claiming that belief of Mary's perpetual virginity is a condition of salvation is only found in the writings of some Pope.
My beliefs are founded on the apostolic church. The beliefs I follow have not evolved over time, but are founded on the rock; belief in Jesus. Salvation is by grace, through faith, for works.