What was one of Charlemagne greates accomplishments?

He created an empire : conquered the Saxons, the Lombards, the Avars. He introduced Christianity among the peoples he ruled over. He was the first Holy Roman emperor. He got his title and the crown from the pope. He encouraged agriculture and trade. As he was a well-educated man himself, he promoted arts and education. He had his splendid palace built in Aachen which became the centre of learning. He invited the best scholars to his court.