The Institutes (Latin: Institutiones) is a component of the Corpus Juris Civilis, the 6th-century codification of Roman law ordered by the Byzantine emperor Justinian I. It is largely based upon the Institutes of Gaius, a Roman jurist of the second century A.D. The other parts of the Corpus Juris Civilis are the Digest, the Codex Justinianus, and the Novellae Constitutiones ("New Constitutions" or "Novels").[1]