The ships—Re Umberto, Sicilia, and Sardegna—were built as the culmination of a major naval expansion program begun in the 1870s following Italy's defeat at the Battle of Lissa in 1866.

They provided fire support to Italian troops fighting in Libya during the conflict and took part in the seizure of several Ottoman ports, including Tripoli.

The Re Umberto class was the culmination of the first phase of the program, which saw ten modern ironclad battleships built; these ships placed Italy with the third largest navy in the world, after Great Britain and France.

[1] The three Re Umbertos were designed by Benedetto Brin, then the president of the Committee for Naval Projects, and who had overseen most of the ironclad construction program.

This was more efficient than the arrangement used in previous designs, with both pairs of guns mounted in a central barbette that limited their arcs of fire.

Close-range defense against torpedo boats was provided by a battery of sixteen 120 mm (4.7 in) guns in casemates in the upper deck aboard Re Umberto, eight on each broadside.

[10] In 1905, all three ships were transferred to the Reserve Squadron,[11] having been supplanted by the more modern pre-dreadnought battleships of the Ammiraglio di Saint Bon and Regina Margherita classes.

[12] The three ships saw significant action during the Italo-Turkish War of 1911–1912, primarily conducting operations in support of Italian troops fighting in Libya.

From October to December 1911, the ships were stationed off Tripoli, where they bombarded Ottoman defenses to prepare for the initial landing and then provided fire support to Italian forces after they had seized the city.

After returning to Italy for resupply,[13] the ships were tasked with escorting troop convoys to attack other ports in Libya from June to August 1912.

After Italy entered World War I in 1915, Sardegna was stationed in Venice as the flagship of the naval forces defending the port and Re Umberto returned to service as a floating battery in Brindisi.