On Architectural practice and arithmetic abilities in Renaissance Italy

The article examines the figure of the architect at work in Renaissance Italy, when a major change occurred in the practice of design with the spread of arithmetic. This deep scientific, technical, methodological, and cultural shift involved the image of the architect and his profession, his relationship with the patron, as well as the cultural conception of architecture. The essay, crossing disciplinary boundaries, analyses some technical aspects of architectural design in early modern Italy only marginally investigated. If proportional systems and architecture’s theoretical questions have been amply studied, the practical culture, the daily professional practice and its working tools, such as the operative arithmetic actually known to architects, have been only sporadically analysed. During the Renaissance, especially in Italy, an important development of mathematics occurred and arithmetic was clarified and simplified so to allow its diffusion, but at the same time those disciplines remained essentially despised by aristocratic and intellectual elites. What was the architects’ role in this moment of deep change? Which was the arithmetic usually employed by them in the design process? When did Hindu-Arabic numbers and fractions became familiar in the field of architecture? In the secular battle between geometry and arithmetic, which system was used in what professional cases? The essay illustrates how architects with different backgrounds responded to this change, through a comparative analysis of all the architectural drawings containing numbers and calculations made by Michelangelo Buonarroti (1475–1564), Baldassarre Peruzzi (1481–1536), and Antonio da Sangallo the Younger (1484–1546).