Reviving the Justinian Code

The Byzantine Emperor Justinian I had many accomplishments, but establishing the Corpus Juris Civilis ("Body of Civil Law"), often referred to as the Code of Justinian, was one of the most lasting. The first main codification of Roman law, it influenced many modern legal systems. It was given the force of law as the sole source of legal interpretation, which made the application of law across the Empire consistent.

Although established in the 6th century, copies were extensive for the centuries that followed (no originals from the 6th century remain). City-states in northern Italy adopted the Justinian Code as they grew and needed more formal systems of law to guide them internally and in their relationships with each other. By the time Frederick I Barbarossa came to the throne it was also being used in his territories north of the Alps.

Frederick began to use the Justinian Code which not only made application of the law consistent over a large area, it also bolstered Frederick's grander claims. Based on a Roman Imperial foundation, the Code embraced the idea of the "divine right of rulership." Frederick, like many worldly rulers in the Middle Ages, was in conflict with the Church over ultimate authority. The Justinian Code gave him a reason to push forward the idea that he had divine authority to do as he liked, such as taking over northern Italy as well as Germany, and clashing with Archbishops.

The Justinian Code was also adopted as the foundation of the Napoleonic Code, which abolished feudalism.

The "divine right of kings" was a common concept in the Middle Ages. One of the earliest examples was offered in the 7th century by Adomnán of Iona; I'll tell you about him next time.