Leaf from Summa de arithmetica, geometria, proportioni et proportionalita by Luca Pacioli, 1494.

We decided to try to identify a random leaf we had in our collection. Obviously from an early book, the type resembles Erhard Ratdolt’s 1484 rotunda (rotunda being a category of blackletter*). Two things made this page unusual: complex fractions in the text, and vernacular Italian (as opposed to Latin, the language of most early European books). A search for the chapter heading “Distinctio nona Tractatus primus” led to the discovery that the page is from the first edition of Summa de arithmetica, geometria, proportioni et proportionalita by Luca Pacioli, printed by Paganinus de Paganinis in Venice in1494.

The man who introduced Europeans to double-entry bookkeeping was a Franciscan monk who published a treatise on Venetian bookkeeping in 1494 in a 27-page section of his vast Summary of arithmetic, geometry, proportions and proportionality. It was a practical instruction book for 15th/16th businessmen.

“By the 1430s the merchants of Venice had perfected a system of double-entry account-keeping …The man responsible for its codification and preservation—the author of the world’s first printed bookkeeping treatise—is Luca Bartolomeo de Pacioli, Renaissance mathematician, monk, magician, constant companion of Leonardo da Vinci. As the origin of all subsequent bookkeeping treatises throughout Europe, Luca Pacioli’s bookkeeping tract is not only the source of modern accounting but also ensured the medieval Venetian method itself survived into our times. And so accountants have named Luca Pacioli the ‘father of accounting’—and any story of double entry must pay him special attention. It is worth examining in some detail not only Pacioli’s life but also his times, because in his century Italy was shaken by a renaissance in mathematics and a communications revolution which both bore directly on the staying power of double entry itself.”
—Jane Gleeson-White (Double Entry: How the Merchants of Venice created Modern Finance)

*This podcast about blackletter’s recent, controversial history is worth listening to.