In 1938 the Fleet Air Arm approached Rolls-Royce and asked whether a larger version of the Merlin could be designed. The requirements were that the new engine have good power at low altitude and that it be reliable and easy to service.[3] Work began on the design of the engine soon afterwards.[nb 1] The design process was relatively smooth compared with that of the Merlin, and the first of three prototype Griffon Is first ran in the Experimental Department on 30 November 1939.[4][5]