Institutes (Gaius) in the context of "Institutes of Justinian"

The Institutes (Latin: Institutiones; from instituere, 'to establish') are a beginners' textbook on Roman private law written around 161 AD by the classical Roman jurist Gaius. They are considered to be "by far the most influential elementary-systematic presentation of Roman private law in late antiquity, the Middle Ages and modern times". The content of the textbook was thought to be lost until 1816, when a manuscript of it − probably of the 5th century − was discovered by Barthold Georg Niebuhr.

The Institutes are divided into four books: The first book considers the legal status of persons (personae), the second and third deal with things (res), while the fourth discusses Roman civil procedure (actiones). The original Latin text with an English translation by Francis De Zulueta covers around 300 pages (with critical notes).