Byzantine emperors organized and preserved Roman law, making a lasting contribution to the medieval and modern worlds. By the fourth century Roman law had become a huge, bewildering mass. Its sheer bulk made it almost unusable.

The emperor Justinian appointed a committee of eminent jurists to sort through and organize the laws. The result was the Corpus Juris Civilis (Body of Civil Law), a multipart collection of laws and legal commentary issued from 529 to 534 that is often simply termed Justinian’s Code. Like so much of classical culture, Justinian’s Code was lost in western Europe with the end of the Roman Empire, but it was rediscovered in the eleventh century and came to form the foundation of law for nearly every modern European nation.