Presumably written at the court of Federico da Montefeltro in Urbino around 1480, this treatise explores subjects of civil and military architecture with an extensive use of drawing. This manuscript attracted the interest of Leonardo da Vinci who became its owner and added his own notes and comments. Drawings of machines form the core of part two of the treatise: devices for measuring the distance between objects not immediately accessible, hydraulic apparatus, carts and systems for lifting heavy weights. Throughout the work, there is a clear presence of classical machines, updated to meet the expectations of the times.