The Codex Justinianeus[1] (Latin for the "Code of Justinian", Justinianeus meaning "of Justinian"[2]), also called Codex Justiniani, is one part of the Corpus Juris Civilis, the codification of Roman law ordered early in the 6th century AD by Justinian I, who was an Eastern Roman (Byzantine) emperor in Constantinople. Two other units, the Digest and the Institutes, were created during his reign. The fourth part, the Novellae Constitutiones (New Constitutions, or Novels), was compiled unofficially after his death but is now also thought of as part of the Corpus Juris Civilis.[3]