On 24 January 1862 the Principality of Moldavia the Principality of Wallachia formally united to create the Romanian United Principalities, the core of the Romanian nation state. In 1866 a new constitution came into effect, giving the country the name of Romania.
The new state remained nominally a vassal of the Ottoman Empire. However, it only acknowledged the suzerainty of the Sublime Porte in a formal way. It had its own flag, anthem, and (from 1867) currency, and conducted its own foreign policy.
In 1877, Romania proclaimed itself fully independent, and on 14 March1881, it became the Kingdom of Romania. After the First World War, Transylvania and other territories were also included.
United Principalities (Romania) 1859–1878, shown in light beige.
By Olahus – Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=3448776