of Paris put the Danubian Principalities under the collective guardianship of the Great Powers in 1856. After special assemblies convoked in Moldavia and Wallachia urged the unification of the two principalities, the Great Powers did not prevent the election of Alexandru Ioan Cuza as their collective domnitor (or ruling prince) in January 1859. The united principalities officially adopted the name Romania on 21 February 1862. Cuza's government carried out a series of reforms, including the secularisation of the property of monasteries and agrarian reform, but a coalition of conservative and radical politicians forced him to abdicate in February 1866. Cuza's successor, a German prince, Karl of Hohenzollern-Sigmaringen (or Carol I), was elected in May. The parliament adopted the first constitution of Romania in the same year. The Great Powers acknowledged Romania's full independence at the Congress of Berlin and Carol I was crowned king in 1881. The Congress also granted the Danube Delta and Dobruja to Romania. Although Romanian scholars strove for the unification of all Romanians into a Greater Romania, the government did not openly support their irredentist projects. The Transylvanian Romanians and Saxons wanted to maintain the separate status of Transylvania in the Habsburg Monarchy, but the Austro-Hungarian Compromise brought about the union of the province with Hungary in 1867. Ethnic Romanian politicians sharply opposed the Hungarian government's attempts to transform Hungary into a national state, especially the laws prescribing the obligatory teaching of Hungarian. Leaders of the Romanian National Party proposed the federalisation of Austria-Hungary and the Romanian intellectuals established a cultural association to promote the use of Romanian. World Wars and Greater Romania Fearing Russian expansionism, Romania secretly joined the Triple Alliance of Germany, Austria-Hungary, and Italy in 1883, but public opinion remained hostile to Austria-Hungary. Romania seized Southern Dobruja from Bulgaria in the Second Balkan War in 1913. German and Austrian-Hungarian diplomacy supported Bulgaria during the war, bringing about a rapprochement between Romania and the Triple Entente of France, Russia and the United Kingdom. The country remained neutral when World War I broke out in 1914, but Prime Minister Ion I. C. Brătianu started negotiations with the Entente Powers. After they promised Austrian-Hungarian territories with a majority of ethnic Romanian population to Romania in the Treaty of Bucharest, Romania entered the war against the Central Powers in 1916. The German and Austrian-Hungarian troops defeated the Romanian army and occupied three-quarters of the country by early