# Pacioli, Luca (1445–1517)

Luca Pacioli was an Italian mathematician and Franciscan monk who wrote several influential
books. His encyclopedic *Summa de arithmetica, geometria, proportioni
et proportionalita* (1494) summarized what was known about contemporary
arithmetic, algebra, geometry, and trigonometry and gave a basis for the
major progress in mathematics which took place in Europe shortly after. *Divina proportione* (1509), with drawings by none other than Leonardo
da Vinci (surely no mathematical text was more impressively illustrated!),
deals with the golden ratio, a subject
that Paciola treats from an architectural standpoint in a second volume.

At his death, Paciola left unpublished a major book, *De viribus amanuensis*,
on recreational problems, geometrical problems, and proverbs. This makes
frequent reference to Leonardo, who assisted him with the project: many
of the problems in this treatise are also in Leonardo's notebooks. Again
it is a work for which Pacioli claimed no originality, describing it as
a compendium.