The Serbian-Bulgarian War occurred in 1885, primarily over territorial disputes following the unification of Bulgaria and Eastern Rumelia. Serbia opposed this unification, fearing it would increase Bulgarian power in the Balkans. The conflict lasted from November 1885 to March 1886, with both sides experiencing significant military engagements. The war ended with a peace treaty that favored Bulgaria, solidifying its territorial gains. Although Serbia did not achieve its objectives, the conflict highlighted the rising nationalism in the Balkans and set the stage for future tensions in the region, contributing to the complex political landscape leading up to World War I.