What was one of Charlemagne's accomplishments?

Charlemagne was King of the Franks and drastically increased the size of their kingdom. He expanded into German and down into Italy (helping the Pope deal with the Lombards). He is also known for the many monasteries he founded throughout his territory and his funding of literacy programs taught by monks*. He is also known to have been extremely ruthless to those who did not convert to Christianity. He massacred an entire Germanic tribe who refused.

*Literacy was very important to him because A. he never learned to read in his life time and B. it would help to spread the Word of God.