Quarto was a unique protected cruiser built by the Italian Regia Marina (Royal Navy) in the 1910s. Her keel was laid in November 1909, she was launched in August 1911, and was completed in March 1913. She was the first Italian cruiser to be equipped with steam turbines, which gave her a top speed of 28 knots (52 km/h; 32 mph). Her high speed was a requirement for the role in which she was designed to serve: a scout for the main Italian fleet.

Quarto was based at Brindisi during World War I; she saw action once, during an attack by the Austro-Hungarian Navy on transports operating in the southern Adriatic. She engaged the Austro-Hungarian cruiser SMS Helgoland but neither ship was damaged and both sides withdrew. Quarto served briefly in East Asian waters in the early 1930s, and supported Italian forces during the Second Italo-Abyssinian War in 1936. The following year she served as the flagship of the Italian forces participating in the non-intervention patrols during the Spanish Civil War; here she was attacked by Republican bombers, although she escaped damage. She was stricken from the naval register in January 1939 and subsequently used in weapons tests with human torpedoes and explosive motorboats. Quarto was sunk in a test with an MT explosive motorboat in November 1940.