LA FILARETE

The Sforza Castle: History and Legend

The Sforza Castle stands as one of Milan’s most iconic monuments, a silent witness to the city’s political and architectural transformations from the 14th century to the present day.

The Visconti Origins

The castle’s story begins in the 1360s, when Galeazzo II Visconti commissioned the construction of the first fortress along the city walls. This residence soon became the seat of the Visconti family under Filippo Maria Visconti, a symbol of the lordly power that dominated Milan. However, in 1447, with the proclamation of the Ambrosian Republic, the Milanese people destroyed the Visconti stronghold as a sign of breaking with tyranny, celebrating the fall of a symbol of oppression.

The Sforza Renaissance

The castle’s destiny changed dramatically in March 1450, when Francesco Sforza, husband of Bianca Maria Visconti, began its reconstruction. Thanks to his military and diplomatic skills, the new duke gained the support of the Milanese, who welcomed him as their lord and restorer of order.

The reconstruction involved some of the most illustrious figures of the time, including architects Antonio di Pietro Averlino, known as Filarete, and Bartolomeo Gadio. The result was an imposing fortress with corner towers and a defensive system integrated into the city walls. The facade was dominated by the central tower designed by Filarete, destined to become the protagonist of a dramatic tale.

The Golden Age and Decline

The Sforza era brought wealth and stability, and the castle was expanded and decorated by Renaissance masters such as Leonardo da Vinci, who painted the famous Sala delle Asse, and Bramante. This golden age ended, however, in the early 16th century with the arrival of the French, who plundered the castle, carried away its treasures, and destroyed much of it.

The 1521 Tragedy and the Legend of Bombarda

In 1521, the most dramatic event in the castle’s history occurred: the explosion of the Filarete Tower, then used as a weapons and ammunition depot. The official version attributed the disaster to lightning, but over time other versions emerged, including a legend particularly beloved by the Milanese.

According to this story, the protagonist was Bombarda, a skilled but notorious Swiss gunner recently arrested in Milan. The French commander Odet de Foix, disturbed by the loud creaking of the statue of the Archangel Michael on the nearby church of San Gottardo, convinced Bombarda to shoot it down with a single cannon shot, promising him and his fiancée Assuntina a pardon in return.

Bombarda succeeded in the task, but that same evening, while awaiting release, he heard Assuntina’s screams: French soldiers were trying to assault her. In a desperate act of revenge, Bombarda grabbed a weapon and, under cover of a violent summer storm, fired toward the ammunition depot of the Filarete Tower, causing a catastrophic explosion that killed over three hundred soldiers. Although probably fictional, this story has become part of Milanese folklore.

Centuries of Foreign Domination

In the following centuries, Milan experienced further upheavals under French, Spanish, and Austrian rule, including the incorporation of the Lombard-Venetian Kingdom into the Austrian Empire in 1815. During this period, the castle served primarily as a fortress and prison, gaining sinister notoriety during the Five Days of Milan in 1848, when its cannons fired on the city under orders from Marshal Radetzky.

The Risorgimento and Rebirth

After the Austrian surrender and Milan’s annexation to the Kingdom of Italy in 1861, the castle was looted by the local population, who even proposed its demolition to erase memories of military oppression. However, historical awareness prevailed and major restoration began.

The tower remained in ruins for centuries, but in 1905 the Filarete Tower was finally rebuilt, based on 16th-century designs and dedicated to King Umberto I, who had been assassinated a few years earlier. This gesture marked the definitive transformation of the castle from a symbol of oppression to a historical heritage of the city, witness to the glories and tragedies that have forged Milan’s identity.

Sforzinda

Sforzinda is the imaginary city described by Filarete, in his Treatise on Architecture. Dedicated to Galeazzo Maria Sforza, the city was never built but combines utopian ideals with references to real projects, such as the Ospedale Maggiore in Milan, whose design echoes Filarete’s description of the city hospital.

Sforzinda is designed on an eight-pointed star plan inscribed in a circle representing the moat. Towers stand at each point, gates at each concavity, with straight roads converging toward a central square. Smaller squares mark the midpoints of the sixteen radial axes.

Filarete also imagined the surrounding landscape with castles and a port city, Plusiopolis. He described monumental buildings such as the lord’s palace, churches, prisons, and the mint. The city’s enormous scale made it impractical. Still, Filarete emphasized functional aspects—navigable canals, zoning by social class, market squares, and drainage systems.

For the attainment of virtue, Filarete designed the Casa della Virtù e del Vizio, an allegorical architectural complex inspired by the theme of Hercules at the Crossroads. Built on a square base with a cylindrical structure, it offered citizens two choices: the arduous path of Virtue, leading upwards through the seven liberal arts to a statue of Virtue crowned by the Muses, or the easy descent into Vice, toward taverns and brothels. Celebrations, triumphs, and public honors awaited those who attained virtue through study and discipline. Virtue, represented as a radiant, armed, angelic figure, was linked with symbols of glory, honey, and bees, embodying the ideal of a collective city designed to generate virtue and happiness.