The Romanian War of Independence is the name used in Romanian historiography to refer to the Russo-Turkish War (1877–78), following which Romania, fighting on the Russian side, gained independence from the Ottoman Empire. On , Romania and the Russian Empire signed a treaty at Bucharest under which Russian troops were allowed to pass through Romanian territory, with the condition that Russia respected the integrity of Romania. Consequently, the mobilization of the Romanian troops also began, and about 120,000 soldiers were massed in the south of the country to defend against an eventual attack of the Ottoman forces from south of the Danube. On , Russia declared war on the Ottoman Empire and its troops entered Romania through the newly built Eiffel Bridge, on their way to the Ottoman Empire. Due to great losses, the Russian Empire asked Romania to intervene. On , the first Romanian Army units crossed the Danube and joined forces with the Russian Army. Romanian proclamation of independence On , in the Romanian parliament, Mihail Kogălniceanu read the act of independence of Romania as the will of the Romanian people. A day later, on , the act was signed by Prince Carol I. For symbolic reasons, the date of May 10 was celebrated as Independence Day, until 1947, since it also marked the celebration of the day when the German Prince Carol first came to Bucharest (May 10, 1866). After the Declaration, the Romanian government immediately cancelled paying tribute to the Ottoman Empire (914,000 lei), and the sum was given instead to the Romanian War Ministry. Initially, before 1877, Russia did not wish to cooperate with Romania, since they did not wish Romania to participate in the peace treaties after the war, but the Russians encountered a very strong Ottoman army of 40,000 soldiers, led by Osman Pasha, at the Siege of Plevna (Pleven) where the Russian troops, led by Russian generals, suffered very heavy losses and were routed in several battles. Conflict Due to great losses, Grand Duke Nikolai Nikolaevich, the Russian commander-in-chief, asked Prince Carol I for the Romanian Army to intervene and join forces with the Russian Army. Prince Carol I accepted the Duke's proposal to become the Marshal of the Russian troops in addition to the command of his own Romanian army, thus being able to lead the combined armed forces to the conquest of Plevna and the formal surrender, after heavy fighting,