Bucharest becomes the capital of Romania.
The 1859 ascendancy of Alexandru Ioan Cuza as prince of both Moldavia and Wallachia under the nominal suzerainty of the Ottoman Empire united an identifiably Romanian nation under a single ruler. On 5 February 1862 24 January Old Style the two principalities were formally united to form the Principality of Romania, with Bucharest as its capital.
On 23 February 1866 a so-called Monstrous coalition, composed of Conservatives and radical Liberals, forced Cuza to abdicate. The German prince Charles of Hohenzollern-Sigmaringen was appointed as Prince of Romania, in a move to assure German backing to unity and future independence. He immediately adopted the Romanian spelling of his name, Carol, and his descendants would rule Romania until the overthrow of the monarchy in 1947.
Following the Russo-Turkish War of 1877–1878, Romania was recognized as an independent state by the Treaty of Berlin, 1878 and acquired Dobruja, although it was forced to surrender southern Bessarabia to Russia. On 15 March 1881, as an assertion of full sovereignty, the Romanian parliament raised the country to the status of a kingdom, and Carol was crowned as king on 10 May.
The new state, squeezed between the Ottoman, Austro-Hungarian, and Russian Empires, with Slavic populations on its southwestern, southern, and northeastern borders, the Black Sea due east, and Hungarian neighbors on its western and northwestern borders, looked to the West, particularly France, for its cultural, educational, and administrative models.
Abstaining from the Initial Balkan War against the Ottoman Empire, the Kingdom of Romania entered the Second Balkan War in June 1913 against the Tsardom of Bulgaria. 330,000 Romanian troops moved across the Danube and into Bulgaria. One army occupied Southern Dobrudja and another moved into northern Bulgaria to threaten Sofia, helping to bring an end to the war. Romania thus acquired the ethnically-mixed territory of Southern Dobrudja, which it had desired for years.
In 1916 Romania entered World War I on the Entente side. Romania engaged in a conflict against Bulgaria but as a result Bulgarian forces, after a series of successful battles, regained Dobruja, which had been previously ceded from Bulgaria by the treaty of Bucharest and the Berlin congress. Although the Romanian forces did not fare well militarily, by the end of the war the Austrian and Russian empires were gone; governing bodies created in Transylvania, Bessarabia and Bukovina chose union with Romania, upheld in 1919 the Treaty of Saint-Germain and in 1920 by the Treaty of Trianon.