Second Balkan War

The Second Balkan War (29 June – 10 August 1913) was a conflict fought between the Tsardom of Bulgaria and its former Balkan League allies, Serbia, Montenegro and Greece, who were later joined by Romania and the Ottoman Empire.

The war began when Bulgaria, unhappy with the division of territory in Macedonia after the First Balkan War, launched attacks on Serbian and Greek forces, who repelled the offensive and pushed into Bulgarian territory. With most of Bulgaria's army committed in the south, Romania intervened from the north. The Ottoman Empire also took advantage of the situation to recover territories lost the previous year.

As Bulgaria suffered military setbacks on multiple fronts and Romanian forces advanced towards its capital, Sofia, it requested an armistice. The war ended with the Treaty of Bucharest, which compelled Bulgaria to cede significant territory: Southern Dobruja to Romania, parts of Macedonia to Serbia and Greece, and Adrianople (Edirne) to the Ottoman Empire under the separate Treaty of Constantinople.

The war altered the political balance in the Balkans and intensified regional tensions. Serbia expanded its territory and influence, heightening its rivalry with Austria-Hungary. Bulgaria, weakened by defeat and territorial losses, would later align with the Central Powers in the First World War.