Leonardo da Vinci’s Giant Crossbow

Although Leonardo’s Giant Crossbow is one of his most popular drawings, it has been one of the least understood. Most scholars have traditionally dismissed its purpose as a mere recreational drawing of a fanciful object, albeit a quintessential example of engineering draughtsmanship. As for the design, there has been no adequate appraisal of Leonardo’s approach, thanks in part to the generally considered implausibility of the drawing’s practical function. This book offers the first in-depth account of the drawing’s likely purpose and its highly resolved design, addressing the machine's context, documentary evidence, a short history of the great crossbow and ballista, the first accurate English translation of the text and the technical specifications, and a detailed analysis of his design process for the crossbow, from start to finish. Dozens of preparatory drawings, along with the recent discovery of nearly invisible metal stylus preparatory incisions under the ink of the Giant Crossbow drawing, are evidence of Leonardo’s intent to offer engineers and other viewers a thorough design of the massive machine. Possibly intended for a treatise on military engineering, the Giant Crossbow is one of the earliest dimetric illustrations, and happens to be the earliest surviving illustrated machine that has proportional components that are proposed to scale. To make sense of these new discoveries, the following study will also address a strategy that had been at the core of Leonardo’s working philosophy: his proportional methods.