Adam Opel founded a Sewing Machine Company in Rüsselsheim in 1862, and in 1885 branched out into manufacturing bicycles. Adam Opel had 5 sons, and after Adam's death the sons started manufacturing motorcars in 1899. From 1902 the agreement to build 'Lutzman' cars was ended and Opel signed a contract to produce the 'Opel-Darracq' under license from the French company. However, the Opel brothers didn't sit still had produced a 1,000 vehicles by 1906, and their 1909 Opel 4/8hp model was reliable and sold well. By 1914 Opel was the biggest German car producer and went into mass production during the 1920s. The Great Depression was difficult for all manufacturers, and particularly so in postwar Germany having to pay reparations, so in 1929 Opel sold out to General Motors. Opel continued to manufacture bicycles until 1936 when they sold this business to NSU. After the Second World War Opel Cars increasingly bowed to the desires of their American owners, and by the early 1970s were producing cars such as Opel Kadett C which was almost identical to the British Vauxhall Chevette, and the Opel Ascona B which was virtually given to Vauxhall to become their Cavalier. By the 1980s only badges differed between Opel and Vauxhall and the cars were often made on the same production lines.