Founded in May 1939, the "Geschwader" (Wing) was a product of a late surge in expanding the size of the "Luftwaffe" medium bomber forces. The formation of the wing began on 1 May 1939 with the creation of the command ("Stab") "Gruppe" (Group) and I. and II./KG 55 (first and second groups). III./KG 55 was formed on 1 November 1939 two months after the outbreak of war in Europe. IV.(Erg.)/KG 55 was formed on 1 August 1940 to train new crews sent to the "Geschwader". The formation's first "Geschwaderkommodore" was Wilhelm Süssmann.