Prototype: Harley-Davidson "Model 0" First model: Harley-Davidson "Model 1" Subcategory: Motor-bicycles Inventors: William S. Harley, Arthur Davidson Producer: Harley-Davidson Motor Company (founded by William S. Harley, Arthur Davidson, Walter Davidson and William A. Davidson in 1903 ) Production start: 1905 - Milwaukee, Wisconsin, USA Prototype features: In early 1901, William S.