# Balkan geopolitical shifts and Ottoman conflicts > Live situation record from CLSTR: https://clstr.news/situations/balkan-geopolitical-shifts-and-ottoman-conflicts > Updated: 2026-10-08T00:37:57.000Z. Sources: 4. Developments: 2. The geopolitical landscape of the Balkans underwent significant transformations during the late 19th and early 20th centuries. Following the 1878 Congress of Berlin, Austria-Hungary established a joint administration in Bosnia and Herzegovina, implementing administrative and infrastructural modernization despite initial armed resistance. By 1912, the regional focus shifted toward the decline of the Ottoman Empire. Montenegro initiated the First Balkan War by declaring war on the Ottoman Empire, prompting the formation of the Balkan League with Bulgaria, Serbia, and Greece. The allied forces, totaling approximately 645,000 troops, defeated the Ottoman military. The conflict concluded with the 1913 London Peace Treaty, which required the Ottoman Empire to cede most of its European territories. However, the division of Macedonia among the victors created new frictions, leading to the Second Balkan War and contributing to the regional instabilities that preceded World War I. ## Timeline ### 2026-10-08: First Balkan War: The 1912 conflict against the Ottoman Empire The First Balkan War began in October 1912 as the Balkan League fought to expel the Ottoman Empire from Europe, leading to major territorial shifts and regional instability. 2 sources. https://clstr.news/cluster/first-balkan-war-the-1912-conflict-against-the-ottoman-empire ### 2026-10-06: Balkan historical shifts: Austro-Hungarian rule and the 1912 Ottoman war Historical accounts detail Austria-Hungary's administration of Bosnia and Herzegovina following 1878 and Montenegro's 1912 declaration of war against the Ottoman Empire as part of the Balkan League. 2 sources. https://clstr.news/cluster/balkan-historical-shifts-austro-hungarian-rule-and-the-1912-ottoman-war --- Cite as: Balkan geopolitical shifts and Ottoman conflicts. CLSTR, https://clstr.news/situations/balkan-geopolitical-shifts-and-ottoman-conflicts