Where did the coronation of Charles the Great take place? Why were these circumstances important

Where did the coronation of Charles the Great take place? Why were these circumstances important to Charles’ contemporaries?

800th year, Charles arrived in Rome was proclaimed emperor, the pope in the Temple placed on his head the imperial crown a rite of caravan with the participation of the highest priests.Since then, it began to spread in Europe, as you know, after the death of Rome, the center of the Great Roman Empire moved east to Constantinople, the capital of the Eastern Roman Empire, the new title of Charles made him equal to the emperor of the Eastern Roman Empire, now Charles has become the ruler of almost the entire western Christian world, centered in the autumn, it is the infection of the Christian world that justifies his military campaigns of the emperor.