Moldovenism is a political term used to refer to the support and promotion of the Moldovan identity and Moldovan culture primarily by the opponents of such ideas. Some of its supporters ascribe this identity to the medieval Principality of Moldavia. Others, in order to explain the current differences between Romanian-speaking inhabitants of the two banks of the Prut River, ascribe it to the long incorporation of Bessarabia in the Russian Empire and the Soviet Union. The opponents, on the contrary, claim that Moldovans and Romanians are a single ethnic group and that the Moldovan identity was artificially created by the USSR. Supporters of Moldovan identity contend that the people of Moldavia historically self-identified as "Moldavian" before the notion of "Romanian" became widespread. The belief that Romanians and Moldovans in Bessarabia and the Moldavian ASSR (MASSR) formed two separate ethnonational groups, speaking different languages and possessing separate historical and cultural traits was also endorsed by the Soviet Union. Historical development Creation of Moldavian ASSR In 1812 the Russian Empire and the Ottoman Empire signed the Treaty of Bucharest (1812), by which Russia annexed the eastern part of the medieval Principality of Moldavia. This territory became known as Bessarabia. Between 1859 and 1866, Principality of Moldavia and the neighbouring Principality of Wallachia united into a single country called Romania. In 1917, when the Russian Empire was disintegrating, a Moldavian Democratic Republic was formed in Bessarabia. In 1918, after the Romanian army gained control of the region, Sfatul Țării proclaimed the independence of the Moldavian Republic and, later, voted for the union with Romania. Soviet Russia contested the outcome of these events and, in May 1919, proclaimed the Bessarabian Soviet Socialist Republic as a government in exile. After the Soviet-organized Tatarbunary Uprising failed, in 1924 a Moldavian ASSR (MASSR) was created within the Ukrainian SSR, just east of the river Dniester that then marked the boundary between the Kingdom of Romania and the Soviet Union. For the purpose of giving MASSR its own identity separate from Romania, Soviet authorities declared the variety spoken by the majority of Moldavians to be "Moldavian language". The intellectual elites of the MASSR were asked to standardise a Moldovan literary language based on the local dialects of MASSR, which are similar to Romanian. Until the 1920s the Russians did not argue that Moldovans and their neighbors in the Romanian Principalities somehow formed nations. One observer wrote in 1846