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Legacy

The work's legacy is profound. Although not a Christian work, in 390 St. Ambrose declared it legitimate for the Church to use (along with everything else Cicero, and the equally popular Roman philosopher Seneca, had written). It became a moral authority during the Middle Ages. Of the Church Fathers, St. Augustine, St. Jerome and even more so St. Thomas Aquinas, are known to have been familiar with it. Illustrating its importance, some 700 handwritten copies remain extant in libraries around the world dating back to before the invention of the printing press. Though this does not surpass the Latin grammarian Priscian's 900 extant handwritten copies, it places De Officiis far above many classical works. Following the invention of the printing press, De Officiis was the third book to be printed—third only to the Gutenberg Bible and Donatus's Ars Minor, which was the first printed book.