Maxime Guillaume, born in 1888, was an agricultural engineer who applied for a French patent for a turbojet engine in 1921. This patent, numbered 534,801, was filed on May 3, 1921, and granted on January 13, 1922. It described the first idea to use a gas turbine to power an aircraft. Guillaume’s design was for an axial-flow turbojet engine. However, the engine was never built because it required better compressor technology that was not yet available at the time.