After John Davenport Siddeley had headed up sales at Dunlop in the early 1900’s and making a name for himself driving a 6hp Diamler car in the Thousand Miles Trial, he decided to open his own car company (Siddeley Autocar) in 1902. Initially starting with Peugeot designs, by 1905 they had more than 12 models for sale. After a few mergers and partnering with different gentlemen, Siddeley ultimately partnered with Sir W. G. Armstrong Whitworth and Co Ltd, which by 1919 included aircraft engines and an aircraft business, in addition to motorcars. Armstrong Siddeley were some of the earliest manufactures to use light alloys for their engines. While more common to use for aircraft, Armstrong Siddeley motors were early adopters of using these components in motor car engines. They used the lightweight alloy for engine pistons and many other motor car parts. Armstrong Siddeley were known for luxury cars and produced motor cars up until 1960.