Charlemagne, also known as Charles the Great, was a medieval ruler who became the first Holy Roman Emperor. He reigned from 768 to 814 and is known for his military conquests and efforts to unite much of Western Europe under his rule. Charlemagne was a patron of the arts and education, and his reign is often associated with the Carolingian Renaissance, a period of cultural and intellectual revival. He is considered one of the most important figures in European history and is remembered for his impact on the development of medieval Europe.