Why was Charlemagne so important even though his empire collapsed after his death?

Charlemagne was crucial for uniting much of Western Europe during the early Middle Ages, laying the groundwork for the future nations of France and Germany. His promotion of education, culture, and Christianity spurred the Carolingian Renaissance, which preserved classical knowledge and influenced European development. Despite the eventual collapse of his empire, his legacy lived on through the establishment of a centralized authority and the concept of a Christian empire, shaping European identity and politics for centuries to come.