The Opus Majus (Latin for "Great Work") is the most important work of Roger Bacon. It was written in Medieval Latin, at the request of Pope Clement IV, to explain the work that Bacon had undertaken. The 840-page treatise ranges over all aspects of natural science, from grammar and logic to mathematics, physics, and philosophy. Bacon sent his work to the Pope in 1267, accompanied by a letter of dedication which was found by F. A. Gasquet in the Vatican Library and published in 1897. It was followed later the same year by a smaller second work, his Opus Minus, which was intended as an abstract or summary of the longer work, followed shortly by a third work, Opus Tertium, as a preliminary introduction to the other two.
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