The site occupies the summit of one of the peaks of the Valdarno side of Montalbano. Compared to other villages, where the continuity of housing has heavily impacted the conservation of the original forms of the site, in Monsummano Alto, the morphology of the medieval castle is singularly intact. It is in this form that it is represented in some of Leonardo da Vinci's drawings, as in the renowned Paesaggio (Florence, Galleria degli Uffizi, Gabinetto dei disegni e delle stampe, n. 8P). The drawing, created in 1473, shows a view of the Fucecchio marsh as seen from Montalbano (Poggio del Belvedere). On the left, in the foreground, we can recognize parts of the walls and towers of a castle, identified as Montevettolini, while on the right, in the distance, we can make out the profile of a walled and turreted castle situated at the top of a an inverted, cone-shaped peak. The position of the point of elevation in relation to other elements of the landscape has made it possible for us to recognize that profile as the castle of Monsummano. This hypothesis is supported by observations relating to the most well-known bird's-eye view maps by Leonardo, representing the middle Valle dell'Arno, like La Valle dell’Arno, Windsor Castle, RL 12685
The town of Montesumano appears for the first time in a document from the year 1005. It involves the sale of a series of assets of the powerful abbey to Count Ildebrando di Rodolfo of the Aldobrandeschi family. The act describes in great detail some goods that are excluded from the sale: the so-called Lama of San Vito, located in the vicinity of the Nievole and defined at its boundaries by a road that goes from Montesumano as far as the bridge over the Nievole.The first mention of a castle at the place called "Monsummano" dates back only to the first decades of the 12th century, when the fortified village already seems to have been part of the possessions of the noble Alberti family. A few decades later, in 1181, the castle of Monsummano was controlled by a collateral branch of the family, represented by forefather Guido di Rodolfo, known as il Borgognone, the same branch of the Alberti that still had rights over the castle of Montevettolini at the beginning of the 13th century. In the act of 1181, the count made available to the city of Lucca his castles of the Valdinievole, strategically decisive, at that time, in defining the territories belonging to the cities of Lucca and Pistoia. The castle of Monsummano, like Montevettolini, was located on the border disputed between the two cities that were in the process of forming, during those years, their respective contado.