Skip to content
BiH Atlas
Era 08 of 161918–1941

The Kingdom of Yugoslavia

The integration of Bosnia into the newly formed South Slavic kingdom, Dr. Mehmed Spaho’s defense of territorial borders, and the devastating Cvetković-Maček partition of 1939.

Following the collapse of Austria-Hungary in 1918, Bosnia and Herzegovina became part of the newly declared Kingdom of Serbs, Croats, and Slovenes, renamed the Kingdom of Yugoslavia in 1929. This interwar period proved politically turbulent. The 1921 Vidovdan Constitution centralized all executive power in Belgrade under the Serbian Karađorđević dynasty, suppressing regional autonomy.

Dr. Mehmed Spaho, leader of the Yugoslav Muslim Organization (JMO), fought tenaciously to preserve Bosnia's historical and geographic administrative borders, utilizing strategic coalition building to protect Bosnian cultural and religious institutions. In 1929, King Alexander I declared a royal dictatorship, abolishing historical borders and dividing the kingdom into nine Banovinas (administrative units) designed to erase regional identities; Bosnia's historic territory was split across four different banovinas, leaving its population politically fragmented.

The final blow to Bosnian territorial integrity came on August 26, 1939, with the Cvetković-Maček Agreement (Sporazum). In a desperate bid to appease Croatian nationalists, the central government partitioned Bosnia's territory between the newly created Banovina of Croatia and Serbian administrative spheres, entirely ignoring Bosnian historical boundaries and setting the stage for subsequent wartime conflicts.

Dated events

  1. December 1, 1918

    Creation of Kingdom of SHS

    Bosnia is absorbed into the new South Slavic state, ending Habsburg administration and introducing Belgrade centralization.

    Actors: King Alexander I, South Slavic politicians

  2. June 28, 1921

    Vidovdan Constitution

    Mehmed Spaho successfully negotiates Article 135, preserving Bosnia's geographical integrity temporarily within administrative borders.

    Actors: Dr. Mehmed Spaho, Nikola Pašić

  3. August 26, 1939

    Cvetković-Maček Agreement

    Bosnia's historic state borders are aggressively partitioned between Zagreb and Belgrade, igniting local political crises.

    Actors: Dragiša Cvetković, Vladko Maček

Sources and verification

Fact-checked 2026-09-11. Errors found in the draft were corrected and logged.