The Treaty of Niš was a peace treaty signed on 3 October 1739 in Niš (East Serbia), by the Ottoman Empire and Russian Empire. The Russo-Turkish War, 1735-1739 was the result of the Russian effort to gain Azov and Crimea as a first step towards dominating the Black Sea. The Habsburg Monarchy entered the war in 1737 on the Russian side, but was forced to make peace with Ottomans at the separate Treaty of Belgrade, surrendering Northern Serbia, Northern Bosnia and Oltenia, and allowing the Ottomans to resist the Russian push toward Constantinople. In return, the Sultan acknowledged the Habsburg Emperor as the official protector of all Ottoman Christian subjects (see Ottoman millet), a position also claimed by Russia. The Austrian peace treaty compelled Russia to accept peace at Niš', forcing