Russo-Persian War, 1722–1723, known in Russian historiography as the Persian campaign of Peter the Great, was a war between Russia and Persia (Safavid Iran), triggered by the tsar's attempt to expand Russian influence in the Caspian and Caucasus regions and to prevent its rival, Ottoman Empire, from territorial gains in the region at the expense of declining Safavid Iran. The territories remained in Russian hands for 9 and 12 years, when respectively according to the Treaty of Resht of 1732 and the Treaty of Ganja of 1735, they were returned to Iran.