ethnic boundaries, for over 1.3 or 1.6 million Hungarian people, representing 25.5 or 31.6% of the Transylvanian population (depending on statistics used), were living on the Romanian side of the border, mainly in the Székely Land of Eastern Transylvania, and along the newly created border. In August 1940, with the arbitration of Germany and Italy under the Second Vienna Award, Hungary gained Northern Transylvania (including parts of Crișana and Maramureș), and over 40% of the territory lost in 1920. This award did not solve the nationality problem, as over 1.15–1.3 million Romanians (or 48% to more than 50% of the population of the ceded territory) remained in Northern Transylvania while 0.36–0.8 million Hungarians (or 11% to more than 20% of the population) continued to reside in Southern Transylvania. The Second Vienna Award was voided on 12 September 1944 by the Allied Commission through the Armistice Agreement with Romania (Article 19), and the 1947 Treaty of Paris reaffirmed the borders between Romania and Hungary as originally defined in the Treaty of Trianon, 27 years earlier, thus confirming the return of Northern Transylvania to Romania. From 1947 to 1989, Transylvania, along with the rest of Romania, was under a communist regime. The ethnic clashes of Târgu Mureș between ethnic Romanians and Hungarians in March 1990 took place after the fall of the communist regime and became the most notable inter-ethnic incident in the post-communist era. Geography and ethnography The Transylvanian Plateau, high, is drained by the Mureș, Someș, Criș, and Olt rivers, as well as other tributaries of the Danube. This core of historical Transylvania roughly corresponds with nine counties of modern Romania. The plateau is almost entirely surrounded by the Eastern, Southern and Romanian Western branches of the Carpathian Mountains. The area includes the Transylvanian Plain. Other areas to the west and north are widely considered part of Transylvania; in common reference, the Western border of Transylvania has come to be identified with the present Romanian-Hungarian border, settled in the 1920 Treaty of Trianon, although geographically the two are not identical. Ethnographic areas: Transylvania proper: Mărginimea Sibiului (Szeben-hegyalja) Transylvanian Plain (Câmpia Transilvaniei/Mezőség) Țara Bârsei (Burzenland/Barcaság) Țara Călatei (Kalotaszeg) (Kővár) Țara Făgărașului (Fogaras) Țara Hațegului (Hátszeg) Țara Moților Țara Năsăudului (Nösnerland/Naszód vidéke) Ținutul Secuiesc (Székelyföld/Székely Land) Banat Crișana Maramureș Țara Oașului (Avasság) (Lápos-vidék) Administrative divisions The area of the historical Voivodeship is . The regions granted to Romania in 1920 covered 23