The Sforza Castle (Italian: Castello Sforzesco [kasˈtɛllo sforˈtsesko]; Milanese: Castell Sforzesch [kasˈtɛl sfurˈsɛsk]) is a medieval fortification located in Milan, northern Italy. It was built in the 15th century by Francesco Sforza, Duke of Milan, on the remnants of a 14th-century fortification. Later renovated and enlarged, in the 16th and 17th centuries it was one of the largest citadels in Europe.

From Wikipedia