In the aftermath of the Russo-Turkish War (1806–1812), and the ensuing Peace of Bucharest, the eastern parts of the Principality of Moldavia, an Ottoman vassal, along with some areas formerly under direct Ottoman rule, were ceded to Imperial Russia. The acquisition was among the Empire's last territorial acquisitions in Europe. The newly acquired territories were organised as the Governorate of Bessarabia, adopting a name previously used for the southern plains between the Dniester and the Danube rivers. Following the Crimean War, in 1856, the southern areas of Bessarabia were returned to Moldavian rule; Russian rule was restored over the whole of the region in 1878, when Romania, the result of Moldavia's union with Wallachia, was pressured into exchanging those territories for the Dobruja.