During the 1877–1878 Russo-Turkish War Romania fought on the Russian side, Romania remained neutral for the first two years of World War I.
Following the secret Treaty of Bucharest, according to which Romania would acquire territories with a majority of Romanian population from Austria-Hungary, it joined the Entente Powers and declared war on 27 August 1916.
In the other parts, many small local states with varying degrees of independence developed, but only under Basarab I and Bogdan I the larger principalities of Wallachia and Moldavia would emerge in the 14th century to fight the threat of the Ottoman Empire.
By 1541, the entire Balkan peninsula and most of Hungary had been conquered and integrated into the Ottoman Empire.
A strong majority of the population identify themselves as Eastern Orthodox Christians and are native speakers of Romanian, a Romance language.
Nationalistic themes became principal during the Wallachian uprising of 1821, and the 1848 revolutions in Wallachia and Moldavia.
After initial advances the Romanian military campaign quickly turned disastrous for Romania as the Central Powers occupied two-thirds of the country within months, before reaching a stalemate in 1917.
The October Revolution and Russian withdrawal from the War left Romania alone and surrounded, and a cease fire was negotiated at Focșani that December.
Following the war, Romania became a socialist republic and member of the Warsaw Pact.
After the 1989 Revolution, Romania began a transition towards democracy and a capitalist market economy.