Hungary–Romania relations
During World War II, Hungary and Romania became allies and participated in the war against the Soviet Union. But after the coup on 23 August 1944 Romania switched sides and fought against Hungary. Consequently, Soviet and Romanian troops invaded Hungary, occupied Northern Transylvania by October 1944 and re-established the Romanian administration in the region in March 1945. The 1947 Treaty of Paris reaffirmed the borders between Romania and Hungary as originally defined in Treaty of Trianon 27 years earlier, thus confirming the return of Northern Transylvania to Romania.
Caraș-Severin County
After World War I, StEG, Banat and most Austro-Hungarian property were taken over by a company named UDR. During the last years of World War II, when Romania was an ally of Nazi Germany, a partisan group, led by Ștefan Plavăț, was active in the mountainous area of the county. The arrival of the communist regime in Romania after World War II and that regime's campaign of nationalization of the mining industry brought tremendous social upheaval in the area.