Romania's entry into the War in August 1916 provoked major changes for the Germans. General Erich von Falkenhayn was dismissed and sent to command the Central Powers forces in Romania, which enabled Hindenburg's subsequent ascension to power. Due to having to fight against all of the Central Powers on the longest front in Europe (1,600 km) and with little foreign help (only 50,000 Russians aided 650,000 Romanians in 1916), the Romanian capital was conquered that December. Vlaicu III was also captured and shipped to Germany, being last seen in 1942. The Romanian administration established a new capital at Iași and continued to fight on the Allied side in 1917. Despite being relatively short, the Romanian campaign of 1916 provided considerable respite for the Western Allies, as the Germans ceased all their other offensive operations in order to deal with Romania. After suffering a tactical defeat against the Romanians (aided by Russians) in July 1917 at Mărăști, the Central Powers launched two counterattacks, at Mărășești and Oituz. The German offensive at Mărășești was soundly defeated, with German prisoners later telling their Romanian captors that German casualties were extremely heavy, and that they "had not encountered such stiff resistance since the battles of Somme and Verdun". The Austro-Hungarian offensive at Oituz also failed. On 22 September, the Austro-Hungarian "Enns"-class river monitor SMS "Inn" was sunk by a Romanian mine near Brăila. After Russia signed the Treaty of Brest-Litovsk and dropped out of the War, Romania was left surrounded by the Central Powers and eventually signed a similar treaty on 7 May 1918. Despite being forced to cede land to Austria-Hungary and Bulgaria, Romania ended up with a net gain in territory due to the Union with Bessarabia. On 10 November, Romania re-entered the War and fought a war with Hungary that lasted until August 1919.