In January 1938, the German Heereswaffenamt requested a lightweight, compact, rapid firing 9 mm weapon for paratroopers and armored crews. The result was the MP 38, a revolutionary submachine gun design which later became the MP 40. However, the MP 38 was produced extraordinarily quickly because Erma-Werke had already produced a prototype submachine gun, the MP 36, before they were even approached to produce one.
The MP 36 was virtually unheard-of even at the time and very few are known to exist. Few were captured by the Allies. The models that were captured mysteriously didn't use their own magazines, instead using MP 40 magazines. Also, the weapons only had one set of markings; they simply read "ERMA ERFURT EMP-36 (Erma Maschinenpistole 1936)". The MP 36 was never likely to have been mass-produced.