The Institutes 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.

Roman law is the legal system of ancient Rome, including the legal developments spanning over a thousand years of jurisprudence, from the Twelve Tables, to the Corpus Juris Civilis ordered by Eastern Roman emperor Justinian I. Roman law forms the basic framework for civil law, the most widely used legal system today, and the terms are sometimes used synonymously. The historical importance of Roman law is reflected by the continued use of Latin legal terminology in many legal systems influenced by it, including common law.