In response to a requirement for a fighter issued by the French Air Force in 1934, Morane-Saulnier built a prototype, designated MS.405, of mixed materials. This had the distinction of being the company's first low-wing monoplane, as well as the first to feature an enclosed cockpit, and the first design with a retracting undercarriage. The entry to service of the M.S.406 to the French Air Force in early 1939 represented the first modern fighter aircraft to be adopted by the service. Although a sturdy and highly manoeuvrable fighter aircraft, it was considered underpowered and weakly armed when compared to its contemporaries. Most critically, the M.S.406 was outperformed by the Messerschmitt Bf 109E during the Battle of France.