IX.] THE NORTHERN MONGOLS. 325 



Uigurs ") in the north. The former had penetrated westwards to 

 the Aral Sea 1 as early as the 2nd century A.D., and many of them 

 undoubtedly took part in Attila's invasion of Europe. 



Later, all these Western Uigurs, mentioned amongst the hordes 

 that harassed the Eastern Empire in the 5th and 6th centuries, 

 in association especially with the Turki Avars, disappear from 

 history, being merged in the Ugrian and other Finnish peoples 

 of the Volga basin. The Toghuz section also, after throwing 

 off the yoke of the Mongol or Tungus Geugen (Jeu-Jen) in the 

 qth century, were for a time submerged in the 



The Assena 



vast empire of the Altai Turks, founded in 552 by Turki 

 Tumen of the House of Assena (A-shi-na), who was 

 the first to assume the title of Kha-Khan, " Great Khan," and 

 whose dynasty ruled over the united Turki and Mongol peoples 

 from the Pacific to the Caspian, and from the Frozen Ocean 

 to the confines of China and Tibet. Both the above-mentioned 

 Singibu, who received the Byzantine envoy, and the Bilga Khan 

 of the Orkhon stele, belonged to this dynasty, which was replaced 

 in 774 by Pei-lo (Huei-hu), chief of the Toghuz-Uigurs. This 

 is how we are to understand the statement that all the Turki 

 peoples who during the somewhat unstable rule of the Assena 

 dynasty from 552 to 774 had undergone many vicissitudes, and 

 about 580 were even broken into two great sections (Eastern 

 Turks of the Karakoram region and Western Turks of the Tarim 

 basin) were again united in one vast political sys- 



Toghuz- 



tem under the Toghuz-Uigurs. These are hence- Uigur Empire, 

 forth known in history simply as Uigurs, the On 

 branch having, as stated, long disappeared in the West. The 

 centre of their power seems to have oscillated between Kara- 

 koram and Turfan in Eastern Turkestan, the extensive ruins of 

 which have been explored by Regel and the brothers Grum 

 Grigimailo. Their vast dominions were gradually dismembered, 

 first by the Hakas, or Ki-li-Kisse, precursors of the present 

 Kirghiz, who overran the eastern (Orkhon) districts about 840, 

 and then by the Muhammadans of Mawar-en-Nahar (Transoxiana), 

 who overthrew the "Lion Kings," as the Uigur Khans of Turfan 



1 They are the Otwt, the "Tens," who at this time dwelt beyond the 

 Scythians of the Caspian Sea (Dionysius Periegetes). 



