The Institutes of Justinian

Laws of the Byzantine Empire, compiled for Emperor Justinian. According to Wikipedia: "The Digesta or Pandectae, completed in 533, is a collection of juristic writings, mostly dating back to the second and third centuries. Fragments were taken out of various legal treatises and opinions and inserted in the Digest. In their original context, the statements of the law contained in these fragments were just private opinions of legal scholars - although some juristic writings had been privileged by Theodosius II's Law of Citaions in 426. The Digest, however, was given complete force of law. As the Digest neared completion, Tribonian and two professors, Theophilus and Dorotheus, made a student textbook, called the Institutiones or Elements. As there were four elements, the manual consists of four books. The Institutiones are largely based on the Institutiones of Gaius. Two thirds of the Institutiones of Justinian consists of literal quotes from Gaius. The new Institutiones were used as a manual for jurists in training from 21 November 533 and were given the authority of law on 30 December 533 along with the Digest.”