'l'heir rulers were the s0-called *Ilak-Khans, or *Kara-
Khans, whose history is more or less known through the works
of Arab and Persian authors, since the conversion of one of the
line—a certain Sátuk Kara Khan—to Islám, in the first half of
the tenth century. That the state and dynasty of the Ilak
Khans were in reality Uighur, there seems to be sufficient
evidence to prove, although the name of Uighur was not used
.by Musulmán authors till a much later date. "They seem to
have been known by the name of T'a-gaz-gaz' until the
thirteenth century, when they begin to appear under that of
Uighur in Western annals, though the Ilak Khans were then no
more. From these same Musulman historians we learn that,
during parts of the tenth and eleventh centuries, the kingdom
of the Ilak Khans extended from Khorasán to China, which is
perhaps scarcely to be taken literally, but is only another way
of saying that it extended a long way to the east; for the
Chinese, in their chronieles of the same period, speak of trans-
actions between their Emperors and the Khans of Kao-Chang
and Bishbálik, as if these were independent chiefs?

We come to surer ground about the year 1124, when Yeliu
Taishi, the Gurkhán of the Kara Khitai, overran the whole of
Fastern Turkistan and eaptured Balssághun, together with
much of the country to the northward, which was then under
the sway of the Ilak Khans. This invasion put an end to the
kingdom of the Western Uighurs—the Kárluks, or Karakháni—
while the Eastern Uighurs became tributary to the conquerors.
