Castello Sforzesco began not with the Sforzas but with the Viscontis, who built a fortress here between 1360 and 1370, straddling Milan's medieval walls. The name Sforza was earned rather than inherited: a thirteen-year-old farmhand named Giacomo threw a hoe into an oak tree to decide his fate, stole his father's horse, and became one of Italy's most feared military commanders. His son Francesco married the last Visconti heir and seized Milan in 1450, transforming the fortress into one of the Renaissance's most lavish courts.

Leonardo da Vinci arrived in 1482 and stayed nearly two decades. By the 1890s the castle was so derelict the city voted to demolish it. Milanese citizens raised the money to save it.

VoiceMap's self-guided audio tours trace this arc from Visconti stronghold to Renaissance court, following Leonardo's footsteps and examining the Michelangelo Pietà Rondanini housed inside the former Spanish garrison infirmary.