The Sforzesco Castle, also known as Castello Sforzesco, is a castle in Milan's historic center that today serves as an art gallery. The site's first building work started in the 15th century. It was rebuilt starting in 1450 by Francesco Sforza, and successive generations made modifications.

The Sempione Park, which consists of a sizable park to the north of the structure, has a square ground plan with a 180-meter side and four angular towers. It has experienced numerous attempts at destruction over the course of its history.

The Visconti family took the initiative to start the first construction in 1358 at Galeazzo II's request. In honor of the name of a neighboring gate, this fortress was referred to as Porta Giova Castle (or Porta Zubia). When the building was finished almost ten years later, it had four corner towers, 200-meter sides, and 7-meter-thick walls. When Galeazzo II passed away in 1378, his sons Gian Galeazzo, Giovanni Maria, and Filippo Maria Visconti took over the throne as his successors. Gian Galeazzo, who immediately established himself as ambitious and bloodthirsty, succeeded him as king. The Certosa di Pavia, the Milan Cathedral (Duomo), and the expansion of the Porta Giovia stronghold were all produced thanks to his passionate sponsorship. The Visconti family's primary residence, the castle, was demolished in 1447 when the short-lived Golden Ambrosian Republic defeated them.

After defeating the republicans in 1450, Francesco I Sforza started to rebuild the castle so that it might serve as his home. He commissioned the artist and architect Filarete in 1452 to create the central tower, currently referred to as Filarete's Tower, and to embellish it. Following Francesco's passing, his son Galeazzo Maria carried on with the building project under the supervision of architect Benedetto Ferrini. Local artists completed the decoration. The tower bearing his name was constructed in 1476, when Bona of Savoy served as regent.

When Ludovico Sforza became Milan's lord in 1494, he commissioned a large number of artists to decorate the castle. Together with Bernardino Zenale and Bernardino Butinone, Leonardo da Vinci created frescoes for a number of rooms. The same was done by Donato Bramante in the Sala del Tesoro, while Francesco Sforza added motions to the Sala della Balla. Leonardo painted embellishments with botanical patterns on the Sala delle Asse ceiling in the early 1498s. However, the fortress suffered harm as a result of attacks by German, French, and Italian troops in the years that followed. A tenaglia, a bastion that was probably created by Cesare Cesariano, was added.

Due to the presence of notable painters like Leonardo, Bramante, and others during the reign of Ludovico the Moor from 1494 to 1499, the castle rose to the status of one of the most opulent courts of the time.

The defeated Maximilian Sforza, his Swiss mercenaries, and the Cardinal Bishop of Sion withdrew into the castle following the French victory at the Battle of Marignano in 1515. King Francis I of France stayed in Milan, nevertheless, and his men planted mines beneath the castle's walls, forcing the defenders to give up. The Filarete Tower was destroyed in a blast in 1521 while it was being utilized as an arsenal. When Francis II Sforza briefly retook control of Milan, he expanded and renovated the stronghold, which was partially converted into Christina of Denmark's home.

It entered Spanish territory in 1535, where it remained until 13 March 1707, when it was turned over to Imperial forces, who had already taken control of Milan at the end of September 1706 following their victory in the siege of Turin during the War of the Spanish Succession.

The Sforzesco Castle was further restored after World War II bombings to its former Sforza-era appearance and was then used as the location of the Gallery of Modern Art (until 1920) and the School of Applied Engineering Art (until 1999).

Numerous museums and significant collections are housed within the Castle complex.

the Egyptian and prehistoric portion of the Milan Archaeological Museum's subsidiary website;

The Armory, the Tapestry Room, and a few burial monuments are all located in the Museum of Ancient Art, along with the final sculpture by Michelangelo, the Rondanini Pietà, the Madonna of Trivulzio by Andrea Mantegna, and the manuscript of the Codex Trivulziano by Leonardo da Vinci.

the painting collection, which features works from the 13th to the 18th centuries. Masterworks by Canaletto, Giovanni Battista Tiepolo, Vincenzo Foppa, Tiziano Vecellio, and Tintoretto are among the works in the art collection.

Numerous drawings and paintings attributed to Caravaggio, also known as Michelangelo Merisi, were uncovered in the castle in 2012. The pieces are said to have been created when Caravaggio was a Milanese student. The pieces may not be by the maestro of the baroque movement, according to Antonio Paolucci, director of the Vatican Museums.

Six unpublished sketches of Leonardo da Vinci that had been buried for centuries beneath multiple layers of plaster were found in 2013.