Leonardo da Vinci and Water: Technical-Economic Knowledge and Hydraulic Infrastructure in Renaissance Milan

This paper explores the interrelation between accounting, hydraulic infrastructure, and inland navigation in Renaissance Milan, through the work of Leonardo da Vinci. Widely recognized for his artistic and scientific genius, Leonardo also played a crucial role in the design and development of the Naviglio della Martesana and other segments of the Milanese canal system (navigli), while serving under Ludovico il Moro. His technical-economic insights reveal a sophisticated understanding of how infrastructure could be both engineered and accounted for. Leonardo’s familiarity with economic-financial calculations and measurement practices was strongly influenced by his intellectual relationship with Fra Luca Pacioli, particularly through the study of Divina Proportione (Pacioli, 1509), which instilled in him a deep grasp of mathematical proportion, geometry, and rational calculation (Vecce, 2017; Marinoni, 1968). This conceptual framework shaped not only his artistic and mechanical designs but also his evaluations of costs, revenues, and logistical efficiency in public works. Leonardo da Vinci also develops the economic and social impact deriving from hydraulic works (Pugno, 2019). Leonardo’s writings, especially within the Codex Atlanticus (Leonardo da Vinci, Codex Atlanticus), document detailed characteristics of vessels navigating the canals, including their dimensions “7 arm’s length e ½ wide, 42 arm’s length long, and 1 arm’s length and ½ deep” and their market value, estimated at 50 gold ducats. He further notes that the Naviglio Grande alone could generate an annual income of 125,000 ducats for the Duchy, emphasizing the strategic role of water-based trade in Milanese fiscal policy and economic governance (Vecce, 2019). Such records reveal Leonardo's awareness of what today we would term cost-benefit analysis and transport economics. They also situate him within a broader Renaissance culture of measurement, management, and accountability in relation to natural resources and mobility systems (Kemp, 2006; Vallerani, 2015). By interpreting these documents through the lens of accounting history, this paper contributes to the growing understanding of how water infrastructures—not only maritime ports but also inland canals—acted as incubators of proto-accounting systems and financial rationality in pre-modern Europe (Bertoloni Meli, 2006).