The Crimean Khanate, was a Turco-Mongol vassal state of the Ottoman Empire during 1478 to 1774, the longest-lived of the Turkic khanates that succeeded the empire of the Golden Horde. It was established by Hacı I Giray in 1449. Its khans were the patrilineal descendants of Toqa Temür, thirteenth son of Jochi and grandson of Genghis Khan. Ottoman forces under Gedik Ahmet Pasha conquered all of the Crimean peninsula and joined it to the khanate in 1475. During the 16th and 17th centuries, it was an important center of the slave trade. In 1774, it was released as a nationally independent state following the Russo-Turkish Treaty of Küçük Kaynarca, and formally annexed by the Russian Empire in 1783, becoming the Taurida Governorate.