In April 1877, in the wake of a new Russo-Turkish war, Romania signed a convention by which Russian troops were allowed to pass through Romanian territory in their advance towards the Ottoman Empire. On May 9, the Romanian parliament declared the independence of the principality, and joined the war on the Russian side. After several Romanian victories south of the Danube and the ultimate victory of the Russian-led side in the war, the European powers recognized Romania's independence under the 1878 Treaty of Berlin. Nevertheless, Romania was made to exchange Southern Bessarabia for Northern Dobruja, and allow non-Christians living in Romania access to Romanian citizenship.