The “State Achievement of Bulgaria 1878” refers to the political establishment of an independent principality within the Ottoman Empire following the Russo-Turkish War (1877-1878). This significant historical event marked the end of over five centuries of Ottoman rule in Bulgaria. The new state, recognized by the Treaty of San Stefano and later confirmed by the Congress of Berlin, encompassed a larger territory than modern-day Bulgaria. It consisted of three vilayets (regions) under the administration of a prince, with the capital city at Sofia. The principality was initially autonomous under the suzerainty of the Ottoman Empire and later gained full independence in 1908, leading to the formation of the Kingdom of Bulgaria.