The German Tiger I, for example, had similar speed and better terrain-handling characteristics when compared to its main competitor, the significantly lighter Panzer IV medium tank.

The origins of the class date to World War I and the first tank designs, which were intended to operate in close concert with infantry.

As lighter and more maneuverable designs were introduced during the Interwar period, these larger vehicles with stronger defensive and offensive capabilities became known as "heavy" tanks.

Heavy tanks had gradually progressed from their trench warfare and bunker destroying role to dedicated anti-tank purposes by the onset of World War II.

The first British tank, the Mark I of World War I, was introduced to break through German defensive lines of trenches and barbed wire.

At the start of World War II, France and the Soviet Union were the only countries to have inventories of heavy tanks, such as the Char B1, T-35, and KV-1.

American forces rarely fielded heavy tanks, as they still held on to the infantry-support doctrine like the British; in addition, the Americans recognized the logistical and mobility issues that came with possessing a heavy tank force and did not want to compromise its 4,800 km (3,000 miles) supply line to Europe.

Near the end of World War II, a few early model M26 Pershings were sent to Europe to gain combat experience.

Both the US and UK developed very well-armoured and armed tanks intended for assaulting heavily defended areas - the T28 GMC and 'Tortoise' had casement designs and weighed around 80 tonnes but did not enter service.