- Invading and rebellious peoples: Charlemagne was continually fighting against invasions from the west by the Vikings and from the east by the Avars. He also faced rebellions from his own subjects, such as the Saxons.
- Power of the aristocracy: The aristocracy had a great amount of power and influence in the Frankish kingdom, and they were often at odds with Charlemagne. This led to conflicts and tensions.
- Church control: Charlemagne sought to control the church and use it as a tool for his own political ends. This brought him into conflict with the pope and other powerful members of the church.
- Economic instability: The economic system was unstable and there were frequent famines and shortages. This made it difficult for Charlemagne to raise taxes and support his government.
- Geographical divisions: Charlemagne's empire was vast and geographically diverse. This made it difficult to communicate and coordinate government activities.
- Political instability: The political system was unstable and succession to the throne was not clear. This led to internal strife and challenges to Charlemagne's authority.
- Lack of infrastructure: Charlemagne's kingdom lacked a well-developed infrastructure, such as roads, bridges, and canals. This hindered communication, trade, and the movement of troops and supplies.
Despite these challenges, Charlemagne was able to achieve a great deal during his reign. He expanded the Frankish kingdom to include most of Western Europe, he revived and reformed the Western Roman Empire, and he promoted Christianity and learning.