In 1460, Francesco I Sforza, the Duke of Milan, realized he needed a royal residence that matched his status. He took control of the ruins of a medieval fortress in Northern Italy and supervised its transformation into a grand and majestic residence over several years. Since then, Sforza Castle has been surrounded by a legend. It’s said that beneath its foundations, the duke devised a vast network of secret passages.
Maps and sketches. A research team from the Polytechnic University of Milan, in collaboration with Codevintec and Sforza Castle, recently discovered the truth behind this legend. Thanks to a 15th-century sketch by Leonardo da Vinci, researchers found that there’s indeed a hidden network of tunnels under the castle.
Archaeologists mapped the castle’s subsoil using advanced technology such as ground-penetrating radar and laser scanning. Their work not only confirmed the existence of the passages documented by da Vinci in the Codex Forster I drawings but also revealed signs of a more extensive system of underground corridors.
History and function of the tunnels. Francesco I Sforza rebuilt Sforza Castle, which his successor, Ludovico Sforza, later embellished. Historians believe that Ludovico Sforza commissioned da Vinci to decorate the castle and design an equestrian monument in honor of his father. During this process, da Vinci documented a system of underground tunnels and passageways that hadn’t been physically identified until now.
Researchers believe these structures had been used for military purposes, although some passages served more personal and ceremonial functions. One notable tunnel connects the castle to the Basilica of Santa Maria delle Grazie, home to da Vinci’s iconic painting The Last Supper and the tombs of the Sforza family. This suggests there may have been private access to the mausoleums of the nobility. Additionally, historians say that Ludovico Sforza may have used this tunnel to visit the tomb of his wife, Beatrice d’Este, who is buried in the church.

Technology and the future of research. The discovery of these tunnels not only improves the understanding of the castle’s architecture but also creates new opportunities for digitally reconstructing the site.
Researchers aim to develop a “digital twin” of Sforza Castle by integrating augmented reality technology. This will allow visitors to explore these previously inaccessible spaces virtually and learn important historical details.
“The goal is to create a digital twin of the Sforza Castle, a digital model that not only represents the current appearance of the Castle but also allows you to explore the past, recovering historical elements that are no longer visible,” Franco Guzzetti, a professor at the Polytechnic University of Milan, pointed out.
And all of this is thanks to da Vinci and his brilliant mind.
Image | Wikimedia Commons/CC BY-SA 4.0 | Sailko
Log in to leave a comment