Having its own state tradition, Transylvania, one of the Hungarian Crown Lands, was deprived of all the remnants of the former autonomy and integrated into a unitary Hungarian state due to the conclusion in 1867 of an agreement on the transformation of the Austrian Empire into a dual Austro-Hungarian monarchy. At the beginning of the 20th century the Romanian national movement of Transylvania was noticeably strengthened, becoming an important centrifugal factor in the Hungarian half of the Empire. As the crisis of the dual system deepened, it was increasingly oriented towards royal Romania and associated the embodiment of its national ideals with the unification of all Romanian lands, which could only be realized on the ruins of the Habsburg monarchy. Following the results of the First World War, which caused the collapse of the Austro-Hungarian Monarchy, Transylvania, by the will of the victorious powers, became an integral part of Romania. Hungarian political opinion extremely painfully perceived the loss of this region, which was closely connected with Hungary by economic and cultural ties. The policy of the Horthy regime, aimed at the revision of the Treaty of Trianon, including the return of Transylvania, enjoyed the widest support in the society. The Transylvanian dispute between Hungary and Romania took a special place among the permanent conflicts originated in the imperfect Versailles system, fraught with new threats to the fragile balance of forces established in the interwar Europe. The coming of the Nazis to power in Germany in 1933 and the approach of a new war translated the revisionist goals from the field of ideology and propaganda into the sphere of practical politics. With the Anschluss of Austria and the dismemberment of Czechoslovakia, the Versailles system was blown up, which opened up prospects for revising the Transylvanian problem. Having transferred the Northern Transylvania to Hungary in August 1940 with a promise to compensate for Romania’s loss at the expense of the territory of the USSR, Hitler tied both of his satellites tightly to the Third Reich. Settlement of the Transylvanian question became possible only in the bipolar Yalta-Potsdam system, when both Hungary and Romania entered the sphere of influence of the USSR.