In his history work
Shajara-i Tarākima, the Khan of
Khiva and historian,
Abu al-Ghazi Bahadur, mentions among the 24 ancient
Turkmen (
Oghuz Turkic) tribes, direct descendants of
Oghuz Khagan. Oghuz Khagan is a semi-legendary figure thought to be the ancient progenitor of Oghuz Turks. translates as "strong". In his extensive history work “
Jami' al-tawarikh” (Collection of Chronicles), the statesman and historian of the
Ilkhanate Rashid-al-Din Hamadani also says that the tribe comes from the oldest of Oghuz Khan's 24 grandchildren who were the patriarchs of the ancient Oghuz tribes, and the name
Kayı means "powerful". Soviet
Sinologist and
Turkologist Yury Zuev based on the analysis of tribal names and
tamgas from
Tang Huiyao, identifies a number of ancient
Central Asian Turkic tribes as Oghuz-Turkmen tribes, one of them is the Kay tribe, whom the
Chinese knew as
Xí 奚 (< MC *
γiei). After examining Chinese sources & consulting the works of other scholars (
Pelliot,
Minorsky), Zuev proposes that the Kay had belonged to the proto-Mongolic
Xianbei tribal union
Yuwen Xiongnu and that Kay had been ethnic and linguistic relatives of the Mongolic-speaking
Khitans, prior to being known as an Oghuz-Turkmen tribe by the 9th century. Likewise, Hungarian scholar
Gyula Németh (1969) links
Kayı(ğ) to the (para-)Mongolic
Qay/
Xí, whom Tibetans knew as
Dad-pyi and
Göktürks knew as
Tatabï; however, Németh's thesis is rejected by
Mehmet Fuat Köprülü among others. Later on, Németh (1991) proposes that
Mg. Qay is derived from
Tk. root
qað- "snowstorm, blizzard"; nevertheless,
Golden points out that
Qay has several Mongolic etymologies:
ɣai "misfortune",
χai "interjection of grief",
χai "to seek",
χai "to hew". Even so, Köprülü rejects scholarly attempts to link the formerly Mongolic Qay/Xi to the Oghuz Turkic tribe Qayı(ğ); he points out that
Kashgari's
Dīwān Lughāt al-Turk distinguished the Qay tribe from the Qayığ branch/sub-tribe of the Oghuz-Turkmen tribe. == History ==