I like where you address, that we assume, we are great thinkers. I actually think the opposite, I feel society today does way less thinking than Charlemagne's times. 

School age children K-12 learn to follow directions and apply principles and formulas. I find that as I talk to coworkers and fellow collegiate students people are way less successful free thinkers.  

Today scholars spend time studying the thinking patterns and try to learn how great historical figures like Charlemagne were able to accomplish great things. 

I also was intrigued when you mentioned Charlemagne was unable to read, did he ever learn to read?