Professor Ferdinand Porsche started a development company in Stuttgart in 1931, and one of his early projects was the design of 3 prototype tractors for 1934 which had petrol engines. Later he developed an air-cooled diesel engine that was available in one cylinder, 2, and 4 cylinders.The designs did not go into series production before World War Two and so Porsche were not permitted to manufacture them postwar. Instead Porsche licensed the design to a German company and to an Austrian manufacturer both companies adding 'System Porsche' to their badging. In 1956 Mannesmann bought the license for the Porsche diesel engine and the German design tractor and produced 125,000 Porsche-Diesel tractors in an old Zeppelin warehouse until 1963.