Cluj-Napoca , commonly known as Cluj, is the second most populous city in Romania, after the national capital Bucharest, and the seat of Cluj County in the northwestern part of the country. Geographically, it is roughly equidistant from Bucharest , Budapest  and Belgrade . Located in the Someșul Mic River valley, the city is considered the unofficial capital to the historical province of Transylvania. From 1790 to 1848 and from 1861 to 1867, it was the official capital of the Grand Principality of Transylvania. Other names for the city include: ; , ; Medieval Latin: Castrum Clus, Claudiopolis; and , Kloiznburg.