Who was the most powerful person in europe during the middle ages?

There are many influential people in Europe during the middle ages. It was the start of the era of thinkers since it served as an opening for Renaissance. These influential people include Leonardo da Vinci, Johannes Gutenberg, St. Augustine, Thomas Aquinas, and St. Francis. However, the most powerful among them all is Charlemagne, who stood as the "Father of Europe". His position as king and Holy Roman Emperor was given to him by the pope. He spread Christianity and built schools. He was also able to conquer some neighboring countries. 

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