The Littorio class, also known as the Vittorio Veneto class, was a class of battleship of the Regia Marina, the Italian navy. The class was composed of four ships—Littorio, Vittorio Veneto, Roma, and Impero—but only the first three ships of the class were completed. Built between 1934 and 1942, they were the most modern battleships used by Italy during World War II. They were developed in response to the French Dunkerque-class battleships, and were armed with 381-millimeter (15.0 in) guns and had a top speed of 30 knots. The class's design was considered by the Spanish Navy, but the outbreak of World War II interrupted construction plans.

The Washington Naval Treaty, also known as the Five-Power Treaty, was a treaty signed during 1922 among the major Allies of World War I, which agreed to prevent an arms race by limiting naval construction. It was negotiated at the Washington Naval Conference in Washington, D.C. from November 1921 to February 1922 and signed by the governments of the British Empire, United States, France, Italy, and Japan. It limited the construction of battleships, battlecruisers and aircraft carriers by the signatories. The numbers of other categories of warships, including cruisers, destroyers, and submarines, were not limited by the treaty, but those ships were limited to 10,000 tons displacement each.