67. Trattato d’abaco/Trattato di aritmetica

Biblioteca Riccardiana, Florence
SENDER: Filippo Calandri
ADDRESSEE: Giuliano de’ Medici
GENERAL INFORMATION: Manuscript on parchment. Datable last quarter of the fifteenth century.

Trattati di abaco (arithmetic handbooks) tended for the most part to be very practical affairs. They were generally produced in affordable paper copies, in small, inexpensive formats and materials, either manuscript or in print, for the use of trainees or travelling merchants – not unlike the Prattica di mercatura which precedes this document (i.e., doc. 66). This one, however, is an exception. The single copy of a highly ornamented luxury item in parchment, it is dedicated to Giuliano de’ Medici, whose coat of arms and other related heraldic icons feature throughout the document. The page displayed here is significant because the tables of numerical equivalences and symbols for the different sorts of currencies use the same design and format employed for traditional canon tables in medieval illuminated manuscripts, whose original function was to establish equivalences between the same episodes in the life of Christ as recorded in each of the four different Gospels. In sharp contrast with its profuse ornamentation, other items in the codex illustrate common banking operations, such as 45r, which features a mathematical operation to calculate the monthly benefits on a loan.

(José María Pérez Fernández)