Final answer:
Charlemagne's influence in medieval Europe can be seen through his conquests and campaigns, his efforts in reorganizing the Church and promoting education, and the legitimization of new rulers through Christianity.
Step-by-step explanation:
Charlemagne, also known as Charles the Great, was an influential ruler in medieval Europe. His conquests and campaigns expanded his empire and united western Europe for the first time since the collapse of Roman authority. Charlemagne's influence extended beyond his own realm as he corresponded with other rulers and facilitated trade.
Additionally, Charlemagne had a significant impact on religion and education. He reorganized the Church, creating a hierarchy of archbishops and promoting learning and classical disciplines. His efforts in reforming Church training and education are known as the 'Carolingian Renaissance'.
Furthermore, Charlemagne's influence can be seen in the legitimization of new rulers through Christianity. The conversion of Germanic kings to Catholic Christianity helped them integrate themselves with their Roman population. Bishops served as administrators and monasteries served as places of education for the new elite.