A number of Central Asian peoples who, over the centuries, were a threat to civilized peoples in Asia and Europe. More specific names, for example Mongol, Turk, Kipchak, emerge for some of these peoples who were constantly moving, often over great distances, and who spoke a variety of related Turkic and Mongol languages. The name “Tartars” is applied specifically to tribesmen living south of the Amur who were defeated by the Ming emperor Yongle in the early 15th century. Papal envoys (c.1250) to the Mongols consistently called them Tartars, probably by association with Tartarus, the place of punishment in the underworld of Greek mythology. The name was also applied to the Golden Horde. Some of the Cossacks (originally Kahsaks, “free men”) on the River Dnieper were Tartars. Later any people of Turkish stock in Russia were called Tartars. In the 15th century the Crimean Tartars formed an independent khanate, which was a tributary to the Ottoman Turks until annexed by Russia in 1783. The khanates of the Volga Tartars came under Russian rule in the 16th century.