The Bosnian Crisis refers to a period of political tension and conflict in the late 19th and early 20th centuries, primarily involving the territories of Bosnia and Herzegovina. In 1908, the Austro-Hungarian Empire formally annexed these regions, which had been under Ottoman Empire control. This move angered Serbia and Russia, leading to increased nationalist sentiments and regional instability. The crisis escalated tensions among European powers, contributing to the complex web of alliances that characterized the pre-World War I era. The annexation was a significant factor in the rising conflicts in the Balkans, ultimately setting the stage for the outbreak of the First World War.