If you want to seriously know about Charlemagne, if you are seriously interested in history and want to know the truth, you're going to HAVE TO crack some actual books, and not just sit back with a Hot Pocket and queue up passive entertainment for the masses on Youtube.
I'm going to bring up Idocracy again, and yes I'm somewhat guilty of getting a certain number of people to go see it, since I keep talking about it. But the movie really had something to say. It made you think, even if those thoughts weren't pleasant to consider.
In the movie, the most popular movie is called "Ass" and it's just a closeup of a butt on the screen passing gas. No one knows whose butt it is, or why it's farting. TV channels are of a similar caliber, such as a show with a single plot: a guy gets smashed in the rocks in countless different ways. THAT is mainstream, popular-level entertainment in the future.
Looking at Youtube, I'd say we're three-quarters of the way there!
As far as literature or content goes, Youtube is worse than comic books, or the back of cereal boxes, used to be considered back in the 80's ("back in the day").
Half of it is lies, distorted, half-truths, and bad sources. And almost none of it has an Imprimatur, or is from a Catholic source.
What I learned about Charlemagne in the seminary is that no, he was not a saint. He was EXTREMELY rough around the edges to say the least.