The Corpus Juris (or Iuris) Civilis ("Body of Civil Law") is the modern name for a collection of fundamental works in jurisprudence, enacted from 529 to 534 by order of Byzantine Emperor Justinian I. It is also sometimes referred to metonymically after one of its parts, the Code of Justinian.
The work as planned had three parts: the Code (Codex) is a compilation, by selection and extraction, of imperial enactments to date; the Digest or Pandects (the Latin title contains both Digesta and Pandectae) is an encyclopedia composed of mostly brief extracts from the writings of Roman jurists; and the Institutes (Institutiones) is a student textbook, mainly introducing the Code, although it has important conceptual elements that are less developed in the Code or the Digest. All three parts, even the textbook, were given force of law. They were intended to be, together, the sole source of law; reference to any other source, including the original texts from which the Code and the Digest had been taken, was forbidden. Nonetheless, Justinian found himself having to enact further laws; today these are counted as a fourth part of the Corpus, the Novellae Constitutiones (Novels, literally New Laws).