His immediate successor appears to have taken the title of Ilak Khan, or ** Great
King" or *Sovereign," which seems to have been perpetuated in that of the
dynasty, though it is often wrongly written Iil-Khan. 'PIhis Ilak Khan (perhaps
Nasr by name) conquered Mávará-un-Nahr about 1008, drove out the Samáni
rulers, and established his authority over the country. "The date of his death
does not appear to be recorded, but he is said, in some accounts, to have been
succeeded by his brother Toghan Khan, who is known to have been reigning at
DBalasághun in 1018. He, again, was succeeded by Arslan Khan L; then
followed Kadir Khan, then Arslan IL, and then a second Bughra, who was in
power in the year 1070; but there may have been others between those named
here. Whether the second Bughra was immediately succeeded by one Mahmud
Khan is not clear, but we learn, at any rate, that a Khan of that name was ruler
of. the Uighur-Ilak kingdom about the year 1124, when the Gur Khán of the
Karakhitai invaded Eastern 'Turkistan and conquered it, together with Bala-
sághun, and perhaps also Western T'urkistan. At about this date, the Uighur
kingdom is represented as coming to an end. But the Karakhitai do not appear
to have disturbed Mávará-un-Nahr, which, as a part of the Uighur dominion, was
administered by vassals or tributary Sultans. "These Sultans continued to govern
till 1213, when the last of them, named Usmán, was killed by Muhammad
Khwárizm Shah, who took possession of the country, and held it until he was
PUn ousted, shortly afterwards, by Chingiz Khan, with the Uighurs as his
allies.
