The Castello Sforzesco, built at the behest of Galeazzo Visconti in the second half of the fourteenth century, was later enlarged by the new lords of Milano under the guidance of Francesco Sforza.
He transformed the building into a military citadel, entrusting the construction of the high tower to architect Antonio Averlino, also called "il Filarete", which today welcomes visitors to the main entrance of the Castle.
Over the centuries, the original structure has undergone many demolitions, reconstructions and restorations. Only at the end of the nineteenth century, when the complex was purchased by the city of Milano, the external fortifications were demolished and further restorations were carried out which transformed the Castle from a military building to a place of culture.
The interior of the Castle is made up of three courtyards (cobblestone with paved paths). It hosts some very interesting museums, including the Museo Egizio and the Museo di Arte Antica, where it is possible to admire the "Sala delle asse" where Leonardo da Vinci painted a large pergola of eighteen mulberry trees, which are intertwined on the vault of the Hall holding up the emblem and the Sforza's coats and arms.
The Hall has been restored and reopened to the public for the 500th anniversary of the artist's death.
Also worth a visit is the Museo della "Pietà Rondanini", an unfinished masterpiece by Michelangelo Buonarroti, located in the ancient Spanish hospital.