Itineraries in the Empolese Valdelsa district

Leonardo, who lived his first years of life in Vinci, had the opportunity to observe the operation of the many mills marking the village surroundings. One of these was even recorded in a drawing by him. On one of the maps in the Codex Atlanticus, we see the sketch of a milling mechanism described by a marginal note as the "mill of La Doccia di Vinci". The mill observed by Leonardo was near the castle, fed by the waters of a long millrace, whose traces remain even today. Those same waters also reached the village and were used to power the municipality’s mill. The public mill, which was next to the village inn, was handed over for the da Vinci family to manage in May of 1478, and we know that Leonardo was also present at the event of formal concession. The countryside around Vinci was also dotted with mills fed by the numerous streams descending from Montalbano. Some of these mills are still well preserved, immersed in the evocative natural environment, among the valleys and hillocks Leonardo frequented in his youth.

One of Leonardo’s most famous maps, folio RL 12278 of the Windsor Collection, includes a broad sector of central Tuscany. In one corner, we can see many of the tributaries on the left side of the middle valley of the Arno, including the Era, the Elsa, and the Pesa, with the stream Virginio. On this folio, Leonardo depicted a series of fortified villages that no longer exist. Leonardo was, in essence, the last witness to the landscape of castles and fortresses that formerly punctuated these hills, but which now have either partly disappeared or turned into something profoundly different. This route, accordingly, touches upon the "invisible" castles, like those of Tonda, or Camporbiano, some traces from which remain in modern tourist accommodation facilities, or like Mommialla, once a fortified house, whose ancient thermal waters have been brought back into activity. Remains of some of these fortresses can still be seen in the form of ruins in a wood, as for the case of the castle of Pietra, or along a road, as for Varna. In one case, it was only by means of archaeological excavations that the remains of the "invisible" castle were brought to light, as for Catignano. In other cases, there are majestic country villas standing today on the summits of the hills where the castles once stood, as for Granaiolo, Cambiano, and Montegufoni; in these, only the small churches remain from the "invisible" castles, now transformed into private chapels.

In the 15th century, Leonardo’s family possessed several houses and estates situated on the hills around the castle of Vinci. The names of these rural places have been preserved for centuries, so that today we can reconstruct the map of the da Vinci family possessions around the countryside outside Vinci. During Leonardo’s time, those lands were identified with the names of parishes, the country churches, which were landmarks for the rural population. Those churches actually existed for a long time and all belonged, in the Middle Ages, to the Counts Guidi, lords of the castle of Vinci. Indeed, they were part of a territory that coincided, literally, with the ancient castle district. Some of these churches, such as San Bartolomeo a Streda, San Zio, and San Pantaleo—Leonardo's mother’s parish—still exist. Others, like Santa Lucia a Paterno, no longer exist. Still others, like the church of San Lorenzo in Arniano, are today in ruins, but still mark the landscape of the Vinci countryside and were part of Leonardo’s memory. After observing the watercourses of the Paterno and Arniano valleys, formerly the lands of the Counts Guidi, Leonardo designed a system to create an artificial reservoir, to be used for powering hydraulic machines. On these hills Leonardo designed the only project conceived for his native land, preserved in three famous Leonardian maps.

The village of Vinci was the place where Leonardo lived during his childhood and early youth. Here stood the home of his grandfather Antonio and of his father, the notary ser Piero da Vinci. In the village, below the bulky mass of the fortress of the Counts Guidi, Leonardo’s family managed the public mill powered by the waters of the rio castellano (castle stream). Next to the mill stood a building that was rented by the youngest of Leonardo's half-brothers, Giovanni, and converted into a “tavern and butcher shop”. This point for refreshment in the village was used mainly by people who were passing by Vinci, on their way up toward the Montalbano passes. To make a butcher shop work, an exercise for the slaughter and sale of meat, it was necessary to have a stream nearby, though for this purpose, the da Vinci family could make use of the channel for the nearby municipal mill they were managing. Some investments made by the da Vinci family into activities linked to refreshment along the travel route over the Montalbano road had already been initiated by Leonardo's father toward the end of the 15th century, and concerned the Anchiano property. Among the houses of the “little farm” he had bought a few years earlier in Anchiano, one was in ruins, while the second, a "chasa da oste" (innkeeper’s house), was under renovation. These were the buildings acquired by the da Vinci family in 1482, known today as Leonardo's Birth House, which had been operating for some time as a place for resting. It is here, in fact, that, years before, Leonardo’s grandfather was constrained to interrupt a game at the table, an out and out "tavern" game, in order to draw up a contract. Also present were two messengers in passing from the Republic of Florence, who had stopped at the tavern at Anchiano, along the road toward the Montalbano passes. From the ridge it was possible to descend toward Bacchereto, the small village Leonardo must have frequented during his youth, and where his paternal grandmother's family lived.

The hills of Greti, and the environs around Vinci up to the river, were the landscapes familiar to Leonardo during his youth. In these places he had the opportunity to observe those elements of nature that, out of mere curiosity, became for him the occasion for scientific reflection. In San Pantaleo, for example, where his mother lived, he had probably been able to observe the fossiliferous clays of the place called colle marino (marine hill). In several passages in the folios of the Codex Leicester, Leonardo elaborated his theory about the way the different geological levels of this area of ​​the Valdarno formed: today we would refer to this as the "Geological Stratigraphy of the Middle Valdarno". Leonardo noted the diversity of the geological formations emerging near Capraia and Montelupo, composed mostly of sandstone pebbles (today visible in the Arnovecchio fossil river bend), by way of comparison with the primarily fossiliferous clays he observed in the so-called "Collegonzi cut". His theories about the ancient sea that once reached the gorge of La Gonfolina explained the origins of the "gravel", the "sand", and the "bluish mud", and above all, the reason for the presence of the famous nichi, the fossil shells he observed in the clayey deposits of the area around Greti. Collections of fossils from the places where Leonardo saw, collected, and drew his nichi are on display in the Museo di Storia Naturale dell’Università di Firenze, in the Museo di Paleontologia di Empoli, and in the Museo Ideale “Leonardo da Vinci” at Vinci.