While the concept of codification dates back to the Code of Hammurabi in Babylon ca. 1790 BC, civil law systems derive from the Roman Empire and, more particularly, the "Corpus Juris Civilis" issued by the Emperor Justinian ca. AD 529. This was an extensive reform of the law in the Byzantine Empire, bringing it together into codified documents. Civil law was also partly influenced by religious laws such as Canon law and Islamic law. Civil law today, in theory, is interpreted rather than developed or made by judges. Only legislative enactments (rather than legal precedents, as in common law) are considered legally binding.