The class's design was considered by the Spanish Navy, but the outbreak of World War II interrupted construction plans.

The first two ships, Littorio and Vittorio Veneto, were operational by the early months of Italy's participation in World War II.

They formed the backbone of the Italian fleet, and conducted several sorties into the Mediterranean to intercept British convoys, though without any notable success.

While en route to Malta, German bombers attacked the fleet with Fritz X radio-guided bombs, damaging Italia and sinking Roma.

Both countries were put under significant pressure from the other signatories to use their allotted tonnage to build smaller battleships with reduced caliber main batteries.

The first Italian design, prepared in 1928, called for a 23,000-long-ton (23,370 t) ship armed with a main battery of six 381 mm (15 in) guns in twin turrets.

[4] Protection and radius of action were sacrificed for speed and heavy armament, though the Italians did not value range, as they operated primarily in the confined waters of the Mediterranean.

By 1930, Germany had begun to build the three Deutschland-class ships, armed with six 280 mm (11 in) guns, and France had in turn laid down two Dunkerque-class battleships to counter them.

In late 1932, Italian constructors responded with a design similar to the Deutschland class, but armed with six 343 mm (13.5 in) guns in triple turrets on a 18,000-long-ton (18,290 t) displacement.

[8] Ultimately, nine 381 mm guns in three triple turrets were adopted as the primary battery for the ships, on a displacement in excess of 40,000 long tons (41,000 t),[9] despite the fact that this violated the established naval treaties.

[13] The ships' propulsion system consisted of four Belluzzo geared steam turbines powered by eight oil-fired Yarrow boilers.

[16] The ships' main battery consisted of nine 381 mm L/50 Ansaldo 1934 guns in three triple turrets, two in a superfiring pair forward and one aft.

A 40 mm thick torpedo bulkhead extended inboard from the base of the main belt before curving down to meet the bottom of the hull.

The riveted joint that connected the interior torpedo bulkhead to the bottom of the hull was not strong enough to sustain the tremendous shear loadings associated with direct contact explosions.

The joints failed even in cases of non-contact explosions, which prevented the hollow drum from collapsing as designed and resulted in massive flooding.

After the entrance of Italy to World War II, the Italian Navy moved the unfinished ship from Genoa to Brindisi, out of fears of French attacks on the vessel.

On the night of 8–9 January 1941, the Royal Air Force attacked Naples with heavy bombers, but failed to hit the ship.

In February, Vittorio Veneto, Andrea Doria and Giulio Cesare attempted to attack what was believed to be a Malta convoy.

[45] Germany pressured the Italian Navy to begin the operation, under the impression that they had disabled two of the three battleships assigned to the British Mediterranean Fleet.

She was then attacked by torpedo bombers from HMS Formidable; the first wave failed, but the second scored a single hit each on both Vittorio Veneto and the heavy cruiser Pola.

[48] Littorio and Vittorio Veneto had both returned to active duty by August 1941, and on the 22nd the two ships sortied to attack a convoy.

While escorting a convoy to North Africa, Vittorio Veneto was torpedoed by the British submarine HMS Urge; repairs lasted until Spring, 1942.

[49] Repairs to Vittorio Veneto were completed in time for her to join Littorio on attacks on the convoys Vigorous and Harpoon, which had departed Alexandria and Gibraltar to reinforce Malta simultaneously in mid-June.

Combat was limited to the opposing light forces, and Littorio and Vittorio Veneto did not see action; the British nevertheless broke off Operation Vigorous due to the battleships' presence and heavy air attacks.

Repairs were completed and on 12 December, both ships were moved from Taranto to La Spezia in response to the Allied landings in North Africa.

In September 1943, following the withdrawal of Italy from the war, all three ships and a significant portion of the Italian fleet left port to be interned in Malta.

[50] In 1939, Spain's General Francisco Franco briefly considered a naval building program after seizing power in the Spanish Civil War.

The Italian Navy pushed to modernize and enlarge the existing shipyards in Spain, so that they could handle a vessel as large as the Littorio class.

The project was abandoned after Italy became involved in World War II, and as a result of limited Spanish industrial capacity.

[51] In the early 1930s, the Soviet Navy began a naval construction program, and sought advice from foreign shipbuilders for a new class of battleships.