The Rolls-Royce 10 hp was the first car to be produced as a result of an agreement of 23 December 1904 between Charles Rolls and Henry Royce, and badged as a Rolls-Royce. The 10hp was produced by Royce's company, Royce Ltd., at its factory in Trafford Park, Manchester, and was sold exclusively by Rolls' motor dealership, C.S.Rolls & Co., at a price of GBP395. The 10hp was exhibited at the Paris Salon in December 1904, along with 15hp and 20hp cars and engine for the 30hp models.
The 10hp was a development of Henry Royce's first car, the Royce 10, of which he produced three prototypes in 1903. This was itself based on a second-hand Decauville owned by Royce which he correctly believed he could improve. In particular, Royce succeeded in making his car significantly quieter than existing cars. Unlike the Royce 10 which had a flat topped radiator, the Rolls-Royce 10hp featured one with a triangular top which would appear on all subsequent cars.