The FV214 Conqueror was conceived in 1946 as a response to two other categories of vehicles: the German panzer tanks that had demonstrated superior firepower during World War II, and the Soviet IS-3 heavy tank that entered service in 1945. The Conqueror(TM)s 120mm gun was considered an advantage, but tank crews generally found the vehicle difficult to maneuver. Once the Centurion was outfitted with a 105mm gun, the Conqueror was withdrawn from use in the 1960s.