In 1600, all three principalities were ruled simultaneously by the Wallachian prince Michael the Brave (Mihai Viteazul), who was considered, later on, the precursor of modern Romania and became a point of reference for nationalists, as well as a catalyst for achieving a single Romanian state.
Nationalistic themes became principal during the Wallachian uprising of 1821, and the 1848 revolutions in Wallachia and Moldavia.
The October Revolution and Russian withdrawal from the War left Romania alone and surrounded, and a cease fire was negotiated at Focșani that December.
Its capital and largest city, Bucharest, is the sixth-largest city in the EU, with 2,106,144 inhabitants as of 2016; other major urban areas include Cluj-Napoca, Timișoara, Iași and Constanța.
The River Danube, Europe's second-longest river, rises in Germany and flows in a general southeast direction for 2,857 km (1,775 mi), coursing through ten countries before emptying into Romania's Danube Delta.
During World War II, Romania was an ally of Nazi Germany against the Soviet Union, fighting side by side with the Wehrmacht until 1944, when it joined the Allied powers and faced occupation by the Red Army forces.
Romania lost several territories, of which Northern Transylvania was regained after the war.