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.
Panteley Kiselov
Bulgaria entered the World War on the side of the Central Powers in 1915. The 4th Division was again part of the Third Army which was tasked with the defense of the Danube against possible Romanian incursions. In late August 1916 Romania declared war on Austria-Hungary. In returned Bulgaria fulfilled the obligations to its allies and declared war on Romania on 1 September 1916. On the same day Kiselov was promoted to major general.