Final answer:
Charlemagne is considered a key figure in European history due to his military conquests, promotion of arts and education, and long-lasting impact on European politics, culture, and religion.
Step-by-step explanation:
Charlemagne is seen as a key figure in European history for several reasons. Firstly, he was the King of the Franks and Lombards, and through his military conquests, he expanded the Frankish kingdom into a vast empire. Secondly, Charlemagne played a significant role in the Carolingian Renaissance, where he promoted arts, education, and the spread of Christianity. Lastly, his reign had a lasting impact on European politics, culture, and religion, setting the foundation for the development of feudalism and influencing the later Holy Roman Empire.
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