 The Treaty of Paris (1856) returned the southern part of Bessarabia (later organised as the Cahul, Bolgrad and Ismail counties) to Moldavia, which remained an autonomous principality and, in 1859, united with Wallachia to form Romania.In 1878, as a result of the Treaty of Berlin, Romania was forced to cede the three counties back to the Russian Empire.Over the 19th century, the Russian authorities encouraged the colonization of Bessarabia by Romanians, Russians, Ukrainians, Germans, Bulgarians, Poles, and Gagauzes, primarily in the northern and southern areas vacated by Turks and Nogai Tatar, the latter having been expelled in the 1770s and 1780s, during Russo-Turkish Wars; the inclusion of the province in the Pale of Settlement also allowed the immigration of more Jews.