ldavia remained in Romanian hands and the invading forces were stopped in 1917. Total deaths from 1914 to 1918, military and civilian, within contemporary borders, were estimated at 748,000. By the war's end, Austria-Hungary and the Russian Empire had collapsed and disintegrated; Bessarabia, Bukovina and Transylvania proclaimed unions with the Kingdom of Romania in 1918. By the 1920 Treaty of Trianon, Hungary was forced to renounce in favour of Romania all the claims of the Austro-Hungarian Monarchy over Transylvania. The union of Romania with Bukovina was ratified in 1919 in the Treaty of Saint Germain, and with Bessarabia in 1920 by the Treaty of Paris.
The Romanian expression România Mare (literal translation "Great Romania", but more commonly rendered "Greater Romania"), generally refers to the Romanian state in the interwar period, and by extension, to the territory Romania covered at the time. Romania achieved at that time its greatest territorial extent (almost 300,000 km/120,000 sq mi), managing to unite essentially all of the territories inhabited by Romanians.
During the Second World War, Romania tried again to remain neutral, but on 28 June 1940, it received a Soviet ultimatum with an implied threat of invasion in the event of non-compliance. Under Nazi and Soviet pressure, the Romanian administration and the army were forced to retreat from Bessarabia as well from northern Bukovina to avoid war. This, in combination with other factors, prompted the government to join the Axis. Thereafter, southern Dobruja was ceded to Bulgaria, while Hungary received Northern Transylvania as result of an Axis arbitration. The authoritarian King Carol II abdicated in 1940, and succeeded by the National Legionary State, in which power was shared by Ion Antonescu and the Iron Guard. Within months, Antonescu had crushed the Iron Guard, and the subsequent year Romania entered the war on the side of the Axis powers. During the war, Romania was the most
