The name Tatars may be used to designate all the inhabitants of the steppe-ocean who were not distinctly Caucasian. By geographical designation they are properly called the Ural-Altaic peoples, while ethnically they constitute the Mongolo-Turki group.[4] Included perhaps among those unclassified peoples who were known of old to the Greek as Scythians, to the Persians as Turanians, and to the Chinese as _Hiung-nu_, the Tatars, despite many differences, show unmistakable kinship, usually in their physical features, always in their language and institutions. They have been grouped since medieval times into two great divisions, the Mongols and the Turks. This division may be said to correspond in a very general way to their greater and lesser resemblance to the Chinese, and to a narrower and wider geographical separation from China. Many tribes possess such intermediate characteristics that they cannot easily be classified as Turks or Mongols;[5] but a tribe that is markedly like the Chinese is clearly Mongol, and a tribe that differs widely from the Chinese is clearly Turkish. If these explanations be adopted, the Turkish peoples are then in general those Tatars who have had the greatest admixture of Caucasian blood. Their original seat seems to have been in Mongolia, but in historic times they had come to occupy the whole central part of the steppe region, from the Desert of Gobi to the Volga, in contact with their Mongol kindred on the east and with Iranians on the south and Slavs on the west. The theory of admixture receives support from the fact that the peoples of the Mediterranean civilization found Mongolians repulsive in appearance, but prized Turkish slaves for their beauty.[6] The name Turk does not appear prominently in the Byzantine and Chinese annals before the fifth century A.D., when the people of a Tatar empire were designated Τοῦρκοι and _Tu-kiu_.[7] The word _Turcae_ was used by classical writers soon after the beginning of the Christian era.[8] The name has been suspected of lying hidden in the _Targitaos_ of Herodotus and the _Togharmah_ of Scriptures. However this may be, ancestral peoples possessing the characteristics of the Turks of course existed, and perhaps appeared in history, in very early times.