In August 1914, when World War I broke out, Romania declared neutrality. Two years later, under the pressure of Allies (especially France desperate to open a new front), on August 14/27 1916 it joined the Allies, for which they were promised support for the accomplishment of national unity, Romania declared war on Austria-Hungary.[59]
The Romanian military campaign ended in disaster for Romania as the Central Powers conquered two-thirds of the country and captured or killed the majority of its army within four months. Nevertheless, Moldova remained in Romanian hands after the invading forces were stopped in 1917 and since by the war’s end, Austria-Hungary and the Russian Empire had collapsed, Bessarabia, Bukovina and Transylvania were allowed to unite with the Kingdom of Romania in 1918. By the 1920 Treaty of Trianon, Hungary renounced in favour of Romania all the claims of the Austro-Hungarian Monarchy over Transylvania.[60] The union of Romania with Bukovina was ratified in 1919 in the Treaty of Saint Germain,[61] and with Bessarabia in 1920 by the Treaty of Paris.[62]
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 (see map). Romania achieved at that time its greatest territorial extent (almost 300,000 km²/120,000 sq mi[63]), managing to unite all the historic Romanian lands.
