Who was Charlemagne and what religion did he use to unite Germanic people?

Charlemagne, also known as Charles the Great, was the King of the Franks and later crowned Emperor of the Romans in 800 AD. He played a crucial role in uniting much of Western Europe during the early Middle Ages, primarily through military conquest and diplomatic alliances. Charlemagne promoted Christianity, specifically Roman Catholicism, as a unifying force among the diverse Germanic tribes, using it to foster loyalty and cultural cohesion. His support for the Church and efforts to spread Christianity helped solidify his power and influence across his empire.