In Leonardo’s day Prato was already a bustling commercial and artistic centre, situated close to major thoroughfares and with many flourishing local industries. It is not surprising that Leonardo viewed the city as a key site in his most ambitious engineering project, one that he would work on for at least forty years – the construction of a navigable canal to divert the waters of the Arno. He hoped to receive financing from the Arte della Lana, the prosperous wool guild of Florence, and to earn handsome profits from the scheme. The city therefore appears on many of the artist’s maps (RL 12277 and RL 12685, Codex Atlanticus, Codex Madrid II).
Many letters concerning an ancestor of Leonardo who was a merchant in Barcelona in the 14th century have recently been discovered in Prato’s Archivio di Stato. Some of Leonardo’s friends, such as Filippino Lippi, originally came from Prato. As an artist, sculptor and scientist interested in technology, Leonardo would doubtless have found much to study in the city, from its fortifications to the weaving machines used in its textile workshops, and works by such noted masters as Donatello and Giuliano da Sangallo.