The Roman Empire of the West ceased to exist by 476 CE, after which the Eastern Empire, based in Constantinople and also known for historical reasons as the Roman Empire, was the sole remnant of past glories.
On Christmas Day 800, Charlemagne, king of the Franks, was crowned in Rome by Pope Leo III with the title of Holy Roman Emperor. Leo not only crowned Charlemagne, he kneeled before him.
The effect was to replace the Emperor in Constantinople as the temporal protector of the Church in the West and signalled an end to the Eastern Emperor's involvement in Western affairs. It was intended by the addition of the word 'Holy' to forge a definitive link between the papacy and Charlemagne's empire.
Charlemagne benefited from the support of the Catholic Church, which legitimized his rule and authority, while the church gained a powerful ally who helped spread Christianity and enforce religious unity throughout his empire. Charlemagne's protection of the church also granted it land, wealth, and influence, strengthening its position in society.
He evidently had the support of the Church as he was crowned emperor by the pope.
Charlemagne
He was successful because he has the Roman Catholic church on his side.
Charlemagne was a Roman Catholic Christian. His ancestor Clovis the Frank was the first frankish ruler to convert to Catholic Christianity which steered the course of his nation and their descendants to be a catholic nation. Charlemagne himself was also very religious and allied with the Catholic Church to create the Holy Roman Empire
Charlamgane died roughly 200 years before the Christian church in Europe split into Western-Catholic and Eastern-Orthodox, meaning he was simply "Christian".
The Catholic Church allowed Charlemagne to have control over many of its politics and practices primarily because he provided strong military support and protection for the Church, helping to defend it against external threats. In return, the Church legitimized his rule through the act of crowning him Emperor, which reinforced his authority and integrated the Church into the governance of the empire. This mutual benefit fostered a powerful alliance that helped to unify and stabilize both the political and religious landscape of medieval Europe.
The Carolingian Renaissance through the medium of the Catholic Church.
Charlemagne was able to protect the church, in particular Pope Leo III from being exiled. He also created a tax system in which the church received taxes from the people. The Carolingian family created strong ties with the church and the Benedictines as well during his reign.
Charlemagne strengthened the Roman church politically by working closely with the Pope to solidify the church's authority over the Christian community. He also implemented policies to promote Christianity as the main religion of his empire, and he granted land and privileges to the church, increasing its wealth and influence. Additionally, Charlemagne's support of education and culture helped to elevate the church's prestige and power.
All of Europe was Catholic from the reign of Charlemagne beginning in 800. He ruled over most of Europe and brought the Catholic Church to the continent.
The King of the Frankish Empire who helped a Catholic pope defend Rome was Charlemagne. In 800 AD, he was crowned by Pope Leo III as Emperor of the Romans, marking the revival of the title in the West and establishing the groundwork for what would later be known as the Holy Roman Empire. This alliance between the papacy and Charlemagne significantly strengthened the church's influence and the political power of the Frankish Empire.