Of this Etruscan-Roman city, Leonardo may have known the walls (extending for a perimeter of around 2.5 km), a feasible hypothesis considering that, in 1503, he bought two small lots of farmland with olive trees, fruit trees and a stone quarry, located close to the Oratory of Sant’Apollinare and the ancient walls. It is highly improbable instead that he knew about the ruins of the theatre and the temple.
Leonardo was interested in the "Fiesole Lake", which in ancient times covered the Florence-Prato-Pistoia plain; he drew the hills of Fiesole on folio 20v of Madrid Ms. II.
In the "Codex on the Flight of Birds" Fiesole is mentioned three times: once for the sighting of a "bird of prey" on March 14, 1505 or 1506, twice for his prophecy on flight from Monte Ceceri, and once in Ms. G, in regard to the "profile of a stone slab from Fiesole".
Noteworthy are the presence of the Roman Theater and the Archaeological Museum, located in the archaeological area, which preserves the testimonies of the long history of Fiesole.