That treaty became one in a series dealing with access to the Bosphorus, the Sea of Marmara, and the Dardanelles. It evolved from the secret 1833 Treaty of Hünkâr İskelesi (Unkiar Skelessi), in which the Ottoman Empire guaranteed exclusive use of the Straits to "Black Sea Powers" (i.e., Ottoman Empire and Russian Empire) warships in the case of a general war.