The Institutes

After the final draft of the Digest was completed, a commission was appoin­ted to prepare a brief introduction to the Digest, which could be used as a textbook for first-year law students instead of Gaius’s Institutes.

Justinian’s Institutes were mostly based on Gaius’s Institutes and his res cottidianae. Many parts of Justinian’s Institutes were taken almost verbatim from the works of Gaius. This is why the emperor referred to him fondly as “our Gaius” (Inst. Proemium §6, Inst. 4.18.5, and Omnem §1). The compilers also used institutes of Florentinus, Marcianus, Ulpian, and probably of Paul, as well as some new imperial constitutions incorporating Justinian reforms. Justinian’s Institutes were published on November 21, 533 under the title Imperatoris Iustiniani Institutiones, and they came into force, along with the Digest, on December 30, 533.

The Institutes comprise four books, divided into titles, and the titles into paragraphs. Unlike the Digest, the Institutes do not mention the juristic writings from which the texts were taken. Like Gaius’s Institutes, Justinian’s Institutes deal first with people, second with things, and finally with actions. They also contain two titles on the duties of judges and on criminal law, which correspond to nothing within Gaius’s Institutes. Based on their stylistic features, books 1 and 2 were probably written by a different author than books 3 and 4. It is possible, therefore, that the two law professors, members

Justinian and the Corpus Iuris 85 of the commission, distributed the work between them. We do not know, how­ever, which part should be attributed to Theophilus and which to Dorotheus.