Budapest (also Buda-Pest in historical texts) (pronounced [ˈbudɑpɛʃt]) is the capital city of Hungary and the country's principal political, cultural, commercial, industrial and transportation center. The official language spoken is Hungarian. Budapest had 1 777 921  inhabitants in 2003, down from a mid-1980s peak of 2.1 million. Budapest became a single city occupying both banks of the river Danube with the amalgamation on 17 November 1873 of right-bank (west) Buda and Óbuda (Old Buda)together with Pest on the left (east) bank. Archeological findings suggest that the first settlers around the Gellert Hill region of Buda were Celts in the first century BC. Óbuda (Oldbuda) had been established as a legionary camp at the Northern frontiers of the Roman Empire in the reign of Tiberius, becoming a munidicipium in the second century AD. Excavations have exposed extensive remains at Aquincum. Pest, a relatively new part of a developing region, was joined to Buda by a permanent bridge, built by British engineer Adam Clark, in the 1840s.