Who was crowned the first Holy Roman Emperor on Christmas Day in the year 800 C.E.?

The first Holy Roman Emperor crowned on Christmas Day in the year 800 C.E. was Charlemagne. This momentous event took place during a ceremony led by Pope Leo III at St. Peter's Basilica in Rome. Charlemagne's coronation symbolized the merging of Roman, Christian, and Germanic elements, marking the revival of the Western Roman Empire and the establishment of what would later be known as the Holy Roman Empire.

Charlemagne had previously expanded his kingdom, uniting much of Western Europe under his rule while promoting learning and culture, often referred to as the Carolingian Renaissance. His leadership not only strengthened the Frankish state but also underscored the close relationship between the church and state during that period. The significance of his coronation lies in the endorsement of his authority by the Pope, which reinforced the notion of divine right and the role of the Catholic Church in legitimizing rulers.

The other historical figures listed do not match the context of the question regarding the specific event of the coronation in 800 C.E., as they lived before or after that date and had different roles in history. For instance, Justinian was an earlier Byzantine Emperor known for his codification of Roman laws, while Augustus was the first Roman Emperor