Why was Charemenge call the holy man emperor?

Charlemagne was often referred to as the "Holy Roman Emperor" because he was crowned by Pope Leo III in 800 AD, which symbolized the fusion of Roman, Christian, and Germanic elements in his rule. This coronation marked the revival of the concept of a unified Christian empire in Western Europe, linking the monarchy to the Church. Charlemagne's efforts to promote Christianity, education, and governance further solidified his reputation as a holy leader. His reign laid the foundations for what would later become the Holy Roman Empire.