vojska Jugoslavije, NOP i DVJ). The changes were meant to reflect the movement's character as a "volunteer army". In November 1942 the movement was renamed into the National Liberation Army and Partisan Detachments of Yugoslavia (Narodnooslobodilačka vojska i partizanski odredi Jugoslavije, NOV i POJ), a name which it held until the end of the war. This last official name is the full name most associated with the Partisans, and reflects the fact that the proletarian brigades and other mobile units were organized into the National Liberation Army (Narodnooslobodilačka vojska). The name change also reflects the fact that the latter superseded in importance the partisan detachments themselves. Shortly before the end of the war, in March 1945, all resistance forces were reorganized into the regular armed force of Yugoslavia and renamed Yugoslav Army. It would keep this name until 1951, when it was renamed the Yugoslav People's Army. Background and origins On 6 April 1941, the Kingdom of Yugoslavia was invaded from all sides by the Axis powers, primarily by German forces, but also including Italian, Hungarian and Bulgarian formations. During the invasion, Belgrade was bombed by the Luftwaffe. The invasion lasted little more than ten days, ending with the unconditional surrender of the Royal Yugoslav Army on 17 April. Besides being hopelessly ill-equipped when compared to the Wehrmacht, the Army attempted to defend all borders but only managed to thinly spread the limited resources available. The terms of the capitulation were extremely severe, as the Axis proceeded to dismember Yugoslavia. Germany occupied the northern part of Drava Banovina (roughly modern-day Slovenia), while maintaining direct military occupation of a rump Serbian territory with a puppet government. The Independent State of Croatia (NDH) was established under German direction, which extended over much of the territory of today's Croatia and as well contained all the area of modern-day Bosnia and Herzegovina and Syrmia region of modern-day Serbia. Mussolini's Italy occupied the remainder of Drava Banovina (annexed and renamed as the Province of Lubiana), much of Zeta Banovina and large chunks of the coastal Dalmatia region (along with nearly all its Adriatic islands). It also gained control over the newly created Italian governorate of Montenegro, and was granted the kingship in the Independent State of Croatia, though wielding little real power within it. Hungary dispatched the Hungarian Third Army and occupied and annexed the Yugoslav regions of Baranja, Bačka, Međimurje and Prekmurje. Bulgaria, meanwhile,