The jurist Gaius — of whom almost nothing is known, not even his full name — writes an elementary manual of Roman law organized into four books (persons, things, succession and obligations, actions), the first known attempt to present Roman law as a coherent system. Its content was believed lost for centuries until in 1816 Barthold Georg Niebuhr discovered a palimpsest manuscript in Verona — the text of Gaius had been scraped off and overwritten with works of St. Jerome. Justinian's Institutes (533) literally copy the structure and numerous passages of this three-centuries-earlier work.