The Regina Maria Pia class was a group of four ironclad warships built for the Italian Regia Marina (Royal Navy) in the 1860s. The class comprised four ships, Regina Maria Pia, San Martino, Castelfidardo, and Ancona. They were built by French shipyards, since Italian yards were unable to meet the demand of the rapidly expanding Italian fleet. The ships were broadside ironclads and mounted a battery of twenty-six muzzle loading guns.