Kingdom of Yugoslavia (1918–1941)
Although the initial split of the country into 33 oblasts erased the presence of traditional geographic entities from the map, the efforts of Bosnian politicians such asMehmed Spaho ensured that the six oblasts carved up from Bosnia and Herzegovina corresponded to the six sanjaks from Ottoman times and, thus, matched the country's traditional boundary as a whole.
The establishment of the Kingdom of Yugoslavia in 1929, however, brought the redrawing of administrative regions into banates or banovinas that purposely avoided all historical and ethnic lines, removing any trace of a Bosnian entity.Serbo-Croat tensions over the structuring of the Yugoslav state continued, with the concept of a separate Bosnian division receiving little or no consideration.
The Cvetković-Maček Agreement that created the Croatian banate in 1939 encouraged what was essentially a partition of Bosnia between Croatia and Serbia.However the rising threat of Adolf Hitler's Nazi Germany forced Yugoslav politicians to shift their attention. Following a period that saw attempts at appeasement, the signing of the Tripartite Treaty, and a coup d'état, Yugoslavia was finally invaded by Germany on 6 April 1941.