The sixteenth-century find “Treatise On Land Surveying Methods Using the Surveyor’s Cross”, by Francesco Paciotti, military and civil architect to the Duchy of Urbino: the technical evolution of a surveying tool.

This paper focusses on the autograph Treatise “On land surveying methods using the surveyor’s cross” found at the Biblioteca Umanistica dell’Università degli Studi di Urbino “Carlo Bo” (“Carlo Bo” Urbino University Humanistic Library). The treatise was for many years erroneously included among the writings of the Urbino mathematician Muzio Oddi (1569-1639), author of Dello Squadro (On the Surveyor’s Cross) of 1625, but through careful bibliographic research has now been attributed to the civil and military architect Francesco Paciotti, (1521-1591). Paciotti’s important knowledge of mathematics and geometry applied to the erection of fortifications and land measurement was essential, too, in the design of an innovative kind of a new surveyor’s cross, which was able to provide more accurate topographic measurements and land surveys. Paciotti extolled the tool as being essential for architecture, and almost certainly used it to build the Citadel of Turin, which provided the model for the construction of all other European citadels and fortresses. The Paciotti’s treatise provides the restorer with a wealth of knowledge on the materials and executive technique used to manufacture the tool.