The Duilio class was a pair of ironclad turret ships built for the Royal Italian Navy (Regia Marina) in the 1870s and 1880s.

They spent the majority of their time in service with the Active and Reserve Squadrons of the main Italian fleet.

In 1895–1898, Enrico Dandolo was heavily reconstructed, but the excessive cost of the modernization prevented Duilio from being similarly rebuilt.

Duilio was stricken from the naval register in 1909 and converted into a floating oil tank, while Enrico Dandolo remained in service as a guard ship during World War I.

[3] In addition, the opening of the Suez Canal in 1869 promised to restore the strategic significance of the Mediterranean; Italy would need a powerful fleet to assert its will and protect its merchant shipping in the region.

The new engines installed in her 1895–1898 refit were slightly more powerful, producing a speed of 15.6 knots (28.9 km/h; 18.0 mph) from 8,045 ihp (5,999 kW).

[5] Duilio and Enrico Dandolo were armed with a main battery of four 450 mm (17.7 in) 100-ton guns of 20-caliber, mounted in two turrets placed en echelon amidships.

The ships' bow and stern were not armored, but they were extensively subdivided into a cellular "raft" that was intended to reduce the risk of flooding.

[11] The lack of armor on both ends of the design sparked controversy: after the former Chief Constructor of the Royal Navy Edward James Reed visited the ships under construction, he criticized this particular design feature, arguing that in case of damage to either end the entering water would have compromised the stability; the new Italian Minister of the Navy, Simone Pacoret di Saint-Bon, replied during a Parliament session that such an event was very unlikely, as it could happen only if all the bulkheads of the watertight compartments were destroyed.

[14] During gunnery trials in March 1880 shortly after entering service, one of Duilio's guns in her aft turret burst.

Italy joined the Triple Alliance with the German Empire and Austria-Hungary in 1882, shortly after the two Duilios entered service; as a result, the country's most likely opponent became France.

[17] The exercises in which the ships took part therefore frequently simulated defensive operations against a hostile, numerically superior French Mediterranean Fleet.

For the 1893 maneuvers, Duilio was part of the squadron that simulated the defending Italian fleet, while Enrico Dandolo operated on the opposing force.

After Italy entered World War I in May 1915, she was transferred to Brindisi and later Venice, where she continued guard ship duties.