He crowned Charlemagne as Holy Roman Emperor.
Charlemagne defeated the Lombards.
When Charlemagne became king of the Franks in 768, he ruled over what is now France and western Germany. After Charlemagne defeated the Lombards in Italy in 800, Pope Leo III crowned Charlemagne as the emperor of the Romans. Charlemagne gained control of most of Italy. During Charlemagne's reign, he had nearly doubled the amount of land he controlled and had united much of western and central Europe.
Charlemagne was the king of the Franks. The pope asked him to attack the Lombards and end their rule in Italy. In exchange he was given the title of Roman emperor. This led to the formation of the Carolingian empire. It has been given this name because it was ruled by Charlemagne and his close relatives (after his death). Italy became part of this empire. Charlemagne was called Roman emperor to symbolise the independence of western Europe from the Roman empire of the East which previously was in charge of part of Italy. The pope also was meant to be a subordinate of this empire. Charlemagne provided the military power that gave the Pope and Italy this independence through his alliance with the pope.
Charlemagne was not prepared for his coronation and may not have wanted to be crowned by the Pope. If the Pope had the power to crown Charlemagne king, the Pope might also have the right to remove the crown.
Pepin the Short was educated by the monks of St. Denis. When he became the effective ruler of the Franks he forced king Childeric III to retire to a monastery and proclaimed himself king with the help of Pope Zachary. It was this pope who dethroned Childeric. He also had him tonsured (this was the shaving off of hair as a sing of religious devotion. Pepin attacked the Lombards in Italy to defend the next pope, Stephen II because they were threatening to take Rome. He also gave the cities he conquered in central Italy to the pope in what has been called the Donation of Pepin. In 772 the Lombards took some the cities Pepin gave to the papacy and marched on Rome. Pope Adrian I demanded that these cities be returned to the papacy and asked Charlemagne for help. Charlemagne attacked the Lomdards in Italy and forced them to leave the papal territories and besieged their capital, Pavia. He confirmed the donation of his father, Pein, and the Pope gave him the title of patrician. In 799 the people of Rome rioted against Pope Leo III, who fled to Charlemagne and asked him to restore him. Charlemagne went to Rome and the pope crowned him Imperator Romanorum (Emperor of the Romans). The pope did so assert Rome's independence from the Byzantine emperors.
Supported the pope; pope crowned Charlemagne Emperor of the Roman people
Charlemagne's Empire was created legally when Pope Leo III crowned him Emperor of the Romans on December 25, 800. The Empire included the Kingdom of the Franks, which he inherited, together with large amounts of territory he conquered and annexed to that kingdom, and the Kingdom of the Lombards, which he also conquered but maintained as a separate kingdom.
Charlemagne subdued Aquitaine and Gascony in south-western France. He fought against the Lombards in Italy to help the pope and took over their kingdom. He took control of the Spanish side of the Pyrenees mountains. He fought against the Saxons and conquered northern Germany. Pope Leo III faced a rebellion in Rome. He was imprisoned in a monastery, but he managed to escape. He then went to see Charlemagne who intervened in his favour and wet to Rome. In Rome Leo III crowned Charlemagne Emperor of the Romans. Charlemagne ruled his empire for 14 years and fell ill with pleurisy and died.
Pépin le Bref (English: Pepin the Short, or Pepin the Younger), first of the Carolingians kings, was the son of Charles Martel and helped the Pope against the Lombards.
The pope gave Charlemagne the title of Holy Roman Emperor, on Christmas Day of 799(?)/800
Charlemagne did not want people to think the pope had the power to choose who was emperor.
Pope Leo III crowned Charlemagne.