Unification Day (Ден на Съединението) on September 6 is a national holiday of Bulgaria. It commemorates the unification of Eastern Rumelia and Bulgaria in 1885. September 6 is the 249th day of the year (250th in leap years). ... The Unification of Bulgaria (Bulgarian language: СÑединение на ÐÑлгаÑиÑ, Suedinenie na Bulgariya) is the act of unification of the Principality of Bulgaria and the then-Ottoman province of Eastern Rumelia in the autumn of 1885. ... Flag of Eastern Rumelia Eastern Rumelia or Eastern Roumelia (Bulgarian: ; Ottoman Turkish: Rumeli-i Sarki; Modern Turkish: Sarki Rumeli, Greek ÎναÏολική ΡÏÎ¼Ï Î»Î¯Î±) was an autonomous province in the Ottoman Empire from 1878 to 1885 (nominally to 1908). ... 1885 (MDCCCLXXXV) is a common year starting on Thursday. ...