Military technology and architecture
The clash between Siena and Florence in 1475 marked Francesco's debut as a military architect and engineer, a field in which he won an immense reputation.
Francesco traveled widely?to Urbino, Milan, Pavia, Naples, Rome, and elsewhere. In 1477, he moved to Urbino and was hired by Duke Federico da Montefeltro. For his new employer, Francesco completed the Ducal Palace, designing the outer frieze composed of 72 stone bas-relief panels. He also built many fortresses in the Montefeltro, with a distinctive round shape to minimize the impact of cannonballs.
Architecture and machines
Francesco's work contains many original machines: weight-moving and weight-lifting machines; water-raising devices; mills; and carriages with complex transmission systems.
In his writings, Francesco displayed an enduring blend of interest in architecture and machines.
The encounter with Leonardo
In 1490, summoned by the Duke of Milan to give an opinion on architectural matters, Francesco met the young Leonardo da Vinci. Leonardo, struck by the competence of his senior colleague, carefully studied Francesco's Treatise on architecture, in which he made some manuscript annotations.