The development of the Maus originates from a contract given to Porsche for the design of a 100-ton tank in March 1942. Porsche's design, known as the "VK 100.01" / "Porsche Type 205", was shown to Adolf Hitler in June 1942, who subsequently approved it. Work on the design began in earnest; the first prototype, to be ready in 1943 was initially to receive the name "Mammut" (Mammoth). This was reportedly changed to "Mäuschen" (Little Mouse) in December 1942 and finally to "Maus" (Mouse) in February 1943, which became the most common name for this tank.