The Ravaldino Fortress is popularly known as the “Fortress of Caterina Sforza”. Built on the foundations of two pre-existing fortifications, it is situated on the highest part of the city, which has always been dedicated to defense. It was commissioned by Pino III Ordelaffi who, in 1471, commissioned the project to the architect Giorgio Marchesi Fiorentino da Settignano.
In 1496, on the remains of the “old fortress”, Caterina Sforza ordered the construction of a ravelin, called “Paradiso”, for the construction of which were used recovery bricks obtained from the demolition of the wing of the Town Hall and the Signoria where the Riario Sforza family and its court resided. After the murder of Girolamo, Caterina and her children, to feel more protected, first moved to the fortress, then to this palace, which was completely lost as a result of the capture of Cesare Borgia.
On April 6, 1498, Ludovico, son of Caterina and Giovanni de’ Medici, made his first cries here, then went down in history as Giovanni dalle Bande Nere, the last of the great Italian leaders and father of Cosimo, the first Grand Duke of Tuscany. The fortress is a typical “transition fortress”, as it was designed and modified in the years when firearms were revolutionizing the way of waging war.
It looks like an imposing quadrangular architecture, with four low cylindrical towers at the corners. The squat male, with a square section, is divided over three floors. From the internal courtyard, access to the keep was via a spectacular spiral staircase in sandstone, still intact but not accessible, which connected the three floors. The unique staircase, without a central pivot, is made up of 67 steps that support each other by overlapping.
The large citadel, where later at the end of the 19th century the prison was built, is defended by only two towers placed in the direction of the city. Citadel and fortress were surrounded by a deep moat, drained and partially filled as the fortress lost its defensive functions. On the curtain it is still possible to admire the coat of arms, made by Cesare Borgia after the bloody battle that caused over six hundred deaths, the capture of the castle and the surrender of Caterina Sforza. The Borgia emblem, in Istrian stone, in which the tiara and papal keys stand out, is walled up in the position where the Valentino soldiers managed to make the breach that, in the evening of 12 January 1500, allowed him to penetrate inside the fortress.