The Opus Majus is a treatise written by Roger Bacon. During the early 16th century, the Assassin Ezio Auditore da Firenze bought a copy of this book from a book shop in Constantinople.


An exemplary specimen of overachievement, this massive book contains treatises on natural science, mathematics, grammar, physics, optics, and philosophy, to name a few. Written for Pope Clement IV as a summary of Bacon's achievements, the "Opus Majus" was evidently not terse enough for his Holiness, and was followed by Bacon's shorter "Opus Minus" just a year after. Whether or not this was later followed by the "Opus Pamphlet" has not been confirmed.