The Great War of superpowers of 1914

Romanian participation

Romania had been allied with the Central Powers since 1882. When the war began, however, it declared its neutrality, arguing that because Austria-Hungary had declared war on Serbia, Romania was under no obligation to join the war. On 4 August 1916, Romania and the Entente signed the Political Treaty and Military Convention, that established the parameters of Romania's participation in the war. In return, it received the Allies' formal sanction for Transylvania, Banat and other territories of Austria-Hungary to be annexed to Romania. The action had large popular support. On 27 August 1916, the Romanian Army launched an attack against Austria-Hungary, with limited Russian support. The Romanian offensive was initially successful in Transylvania, but a Central Powers counterattack drove them back. As a result of the Battle of Bucharest, the Central Powers occupied Bucharest on 6 December 1916. Fighting in Moldova continued in 1917, but Russian withdrawal from the war in late 1917 as a result of the October Revolution meant that Romania was forced to sign an armistice with the Central Powers on 9 December 1917.

In January 1918, Romanian forces established control over Bessarabia as the Russian Army abandoned the province. Although a treaty was signed by the Romanian and Bolshevik Russian governments following talks between 5 and 9 March 1918 on the withdrawal of Romanian forces from Bessarabia within two months, on 27 March 1918 Romania formally attached Bessarabia, inhabited by a Romanian majority, to its territory, based on a resolution passed by the local assembly of that territory on its unification with Romania.

Romania officially made peace with the Central Powers by signing the Treaty of Bucharest on 7 May 1918. Under the treaty, Romania was obliged to end the war with the Central Powers and make small territorial concessions to Austria-Hungary, ceding control of some passes in the Carpathian Mountains, and to grant oil concessions to Germany. In exchange, the Central Powers recognised the sovereignty of Romania over Bessarabia. The treaty was renounced in October 1918 by the Alexandru Marghiloman government, and Romania nominally re-entered the war on 10 November 1918 against the Central Powers. The next day, the Treaty of Bucharest was nullified by the terms of the Armistice of Compiègne. Total Romanian deaths from 1914 to 1918, military and civilian, within contemporary borders, were estimated at 748,000.