Oskar Barnack, who was in charge of research and development at Leitz, decided to investigate using 35 mm cine film for still cameras while attempting to build a compact camera capable of making high-quality enlargements. He built his prototype 35 mm camera (Ur-Leica) around 1913, though further development was delayed for several years by World War I. It wasn't until after World War I that Leica commercialized their first 35 mm Cameras. Leitz test-marketed the design between 1923 and 1924, receiving enough positive feedback that the camera was put into production as the Leica I (for Leitz camera) in 1925. The Leica's immediate popularity spawned a number of competitors, most notably the Contax (introduced in 1932), and cemented the position of 35 mm as the format of choice for high-end compact cameras.