(1833) Alliance between the Ottoman Empire and Russia, signed at the village of Hünkâr İskelesi (Unkiar Skelessi), near Istanbul.
In return for Russian military aid, the Ottoman sultan, Mahmud II, agreed to a secret article in their mutual defense treaty that closed the Dardanelles Strait to any foreign vessels of war except those of Russia. The treaty made the Ottoman Empire a virtual protectorate of Russia. When other countries became suspicious of the agreement, Russia abandoned its Dardanelles privileges in 1841.