Rocca Costanza

Rocca Costanza is a square Renaissance fortress in Pesaro, with four cylindrical corner towers and curtain walls. Commissioned by Costanzo Sforza, it was built between 1474 and 1483 and later served as a barracks and city prison.

Why it matters

The fortress is a significant example of the lowland military architecture developed for cannon-age defence. Its regular plan and corner towers give the structure a clear geometric form. Its later uses—as a papal barracks and, from 1864 to 1989, as a prison—are also part of its history.

What to notice

The square plan is defined by four circular towers connected by curtain walls. Spiral staircases rise within the towers. The moat was completed in 1503 under Giovanni Sforza; local tradition associates Leonardo da Vinci with advice on its design, though this remains a tradition rather than a documented attribution.

Context and history

Costanzo Sforza built on defensive works begun by his father, Alessandro. Construction took place between 1474 and 1483, interrupted by plague. Giorgio Marchesi da Settignano began the work; Luciano Laurana may have continued it, and Cherubino da Milano completed it. Cesare Borgia seized Pesaro in 1500. After the Borgia period, Giovanni Sforza completed the moat. In 1513 Galeazzo Sforza sold the fortress to Francesco Maria I della Rovere. After the duchy passed to the Papal States in 1631, the Rocca became a barracks for papal troops. It was converted into a prison in 1864 and remained one until 1989. The fortress is now managed by the Ministry of Culture.