The Castello di San Giorgio stands near the bridge of the same name, within the monumental complex of Palazzo Ducale. Commissioned by Francesco I Gonzaga, its construction began in 1395 under the direction of Bartolino da Novara. The castle is built of brick with a square plan featuring four corner towers and counter-towers to defend the three gates equipped with drawbridges. The building perfectly combined defensive requirements with the desire to demonstrate the power of the lords of Mantua. However, it did not remain a strategic fortification for long: on the occasion of the Council of Mantua (1459), Ludovico II converted it into a residence, entrusting its remodeling to Luca Fancelli, who gave the building a Renaissance appearance. The basements of the Castle, located level with the moat, housed the infamous prisons since the Gonzaga era, which are currently undergoing a massive renovation and recovery project.