According to Edward Gibbon, writing in the late eighteenth century, the most important legacy of the Age of Justinian and indeed the most important legacy of the emperor himself lay in the field of law. Gibbon’s assessment still rings true. Though the physical boundaries of medieval Europe were recast repeatedly on battlefields long after the Age of Justinian had ended, the law issued in his name still shapes legal culture today.

The “fair and everlasting monument” Justinian bequeathed to posterity is known today as the Corpus iuris civilis: three codices or books of law, promulgated between the years 529 and 534. The Justinianic Codex, the Digest (or Pandects), and the Institutes sought to harmonize 1,000 years of complex and checkered development in the citizen law of the Romans. Justinian’s new law books contained old wine in new skins; each book utilized and incorporated different types of legal source material from the Roman past, but each also reshaped that material, harmonizing disparate texts with each other, mapping the outline of a system of law in a single body (corpus) of interlocking texts.