History of Transylvania union of Transylvania with Romania in Alba Iulia on 1. December 1918.; Bessarabia, having declared independence from Russia in 1917 at the Conference of the Country (Sfatul Țării), called in Romanian troops to protect the province from the Bolsheviks. The union of the Transylvania, Maramureș, Crișana and Banat regions with the Old Kingdom of Romania was ratified in 1920 by the Treaty of Trianon, which recognised the sovereignty of Romania over these regions and settled the border between the Republic of Hungary and the Kingdom of Romania. The union of Bukovina and Bessarabia with Romania was ratified in 1920 by
Northern Transylvania After the Roman legions withdrew in 271 AD, it was overrun by a succession of various tribes, bringing it under the control of the Carpi, Visigoths, Huns, Gepids, Avars and Slavs. From 9th to 11th century Bulgarians ruled Transylvania. The Magyars conquered much of Central Europe at the end of the 9th century and for almost six hundred years, Transylvania had been a voivodeship in the Kingdom of Hungary. After the Battle of Mohács in 1526, and the Hungarian defeat by the Ottomans, Transylvania became a semi-independent principality (Principality of Transylvania) under native Hungarian rule but owing suzerainty to the