How did Charlemagne govern such a large and diverse empire?

Charlemagne governed his vast and diverse empire by refining existing administrative techniques and strengthening the personal ties between himself and his subjects. He relied on several key strategies to maintain control:1

• Centralized Administration: Charlemagne utilized his palatium—an itinerant court of family, trusted companions, and officials—to manage resources, conduct diplomacy, and enforce policies as he traveled across his realm.1
• Local Governance: He relied on counts to represent royal authority in territorial counties, while bishops and abbots were granted immunity to govern their own properties under royal favor.1
• Supervision: To ensure local officials remained loyal and effective, Charlemagne expanded the use of missi dominici. These royal agents, typically one cleric and one layman, conducted regular inspection circuits to investigate abuses and announce the king's will.123
• Legal and Social Bonds: He used capitularies to issue standardized laws and required all free subjects to swear an oath of fidelity. He also utilized the lord-vassal system, granting land and offices in exchange for loyalty and military service.13
• Religious Integration: Charlemagne viewed his kingship as a divine responsibility, integrating religious reform into public policy to unify his subjects under a shared spiritual and moral framework.14