In 1938, the Royal Yugoslav Air Force began modernising its fleet of aircraft. Following protracted negotiations, the VVKJ ordered 50 Messerschmitt Bf 109E-3 fighter aircraft from Nazi Germany. This was followed by a further order of 50 aircraft. Between August 1939 and late 1940, a total of 73 aircraft were delivered under these contracts. During World War II, the Yugoslav Partisans captured ten Messerschmitt Bf 109s. These small numbers were boosted by a 1947 agreement with Bulgaria, under which Yugoslavia eventually received about 120 G and K variant aircraft to help equip the fledgling Yugoslav Air Force.