The development of tank designs at the turn of the 1920s and 1930s, with virtually no effective anti-tank defense systems, led to the creation of supertanks - heavy multi-turreted combat vehicles. Indeed, with almost the same thickness of armor, a heavy tank should logically differ from a light one with more powerful weapons. Therefore, the English (and the British were then the trendsetters in tank construction) heavy tank "Independent," which served as the prototype for the Soviet heavy tank T-35, carried a 47-mm gun as the main weapon, the same as the light Vickers 6-ton, but armed with four more machine guns in rotating towers.