You keep making a big deal about it, as if the lack of historical certainty somehow undermines the entire Catholic belief system. It's simply not important, and I wonder why you think it is so.
SD
The Decretals were used by the Roman church to usurp authority it did not by right have any claim to. The system that developed from there on was developed from fraudulent authority based in lies. Now if you want to say that isn't an invalidation, then you are deluding yourself. Non-authority doesn't become authoritative just because you believe it. As regards myself, I'm certainly not stupid enough to buy into it. Knowing the truth ahead of time, there is no way I can ever view the Roman Church as having any legit authority. The Orthodox have their own problems. They are closer to Christianity than Romanism; but, I'm not buying into either. I have the real thing. I have Jesus living in me and the Holy Spirit operating in my life. I don't need to look to false doctrine to find what I already have. I can command demons in Jesus name because I have that authority as a child of God. I have done so. When you've seen creative miracles, you can't accept fraud for the real thing either.