The Zara class was a group of four heavy cruisers built for the Italian Regia Marina (Royal Navy) in the late 1920s and the early 1930s. The class comprised the vessels , , , and , the last of which was completed to a slightly different design. The ships were a substantial improvement over the preceding s, incorporating significantly heavier armor protection at the cost of the very high speed of the Trentos. They carried the same main battery of eight guns and had a maximum speed of . Among the best-protected heavy cruisers built by any navy in the 1930s, the heavy armor was acquired only by violating the terms of the Washington Naval Treaty, which limited cruiser displacement to . All four ships served with the main fleet in the interwar period, where they were primarily occupied with training exercises and fleet reviews. During the Spanish Civil War, Gorizia evacuated Italian nationals and Pola took part in non-intervention patrols. All four ships supported the Italian invasion of Albania in April 1939, shortly before the outbreak of World War II. After Italy joined the wider conflict in 1940, the four ships saw extensive action in the Mediterranean Sea against British forces. The ships took part in the battles of Calabria and Cape Matapan, and in the latter engagement, Zara, Pola, and Fiume were all sunk in a one-sided night action with three British battleships. Gorizia continued in service, seeing further action at the First and Second Battles of Sirte. She was seriously damaged by American heavy bombers in April 1943 and towed to La Spezia, where she was still under repair when Italy surrendered in September. Germany seized the ship when they occupied the port, and Italian commandos unsuccessfully attempted to sink her in June 1944. In poor condition by the end of the war, the postwar Italian Navy decided to sell the ship for scrap in 1947. Design While the preceding of heavy cruisers were still being built, elements of the Italian naval command began to doubt the effectiveness of the new vessels, which sacrificed armor protection in favor of very high speeds. They advocated a more balanced design that would incorporate more comprehensive armor, with a main belt that was thick, while retaining the battery of eight guns and a speed of at least . The designers quickly found that these characteristics could not be incorporated into