Brothers Robert Morane (1886-1968) and Leon Morane (1885-1918) began designing airplanes almost at the dawn of heavier-than-air aviation in the 1900s. By 1911 they had teamed with Robert Saulnier (1881-1964) to form Morane-Saulnier, one of the most prolific French designers and manufacturers of airplanes throughout the First World War, the 1920s and 1930s, and into the Cold War era. They designed sport, racing and military aircraft of most types until it got caught up in the French aircraft industry socialization and consolidation of the 1960s, eventually becoming part of Aerospatiale.
Early Morane-Saulnier types were designed by letters, and they were so prolific that they exhausted the alphabet and started over with the model AA, AB and so forth; then they worked through the alphabet a second time and started in on a third, with a B-prefix. And this was by 1915! At that point they switched to model numbers which continued through the early 1960s, when the final aircraft designs identifiable as Morane-Saulniers were produced.