What medieval ruler promoted art and architecture in his courtcrowned holy Roman emperor in Rome in 800?

The medieval ruler who promoted art and architecture in his court and was crowned Holy Roman Emperor in Rome in 800 is Charlemagne. He played a significant role in the Carolingian Renaissance, fostering a revival of art, culture, and education. Charlemagne's reign saw the construction of grand buildings, such as the Palatine Chapel in Aachen, which exemplified the era's architectural advancements. His patronage laid the groundwork for the development of medieval European culture.