Oghuz and Oghuz distinct and Ibn al-Faqih mentioned "the infidel Turk-Oghuz, the Toquz-Oghuz, and the Qarluq" Even so, Golden notes the confusion in Latter Göktürks' and Uyghurs' inscriptions, where Oghuz apparently referred to Toquz Oghuz or another tribal grouping, who were also named Oghuz without a prefixed numeral; this confusion is also reflected in Sharaf al-Zaman al-Marwazi, who listed 12 Oghuz tribes, who were ruled by a "Toquz Khaqan" and some of whom were Toquz-Oghuz, on the border of Transoxiana and Khwarazm. At most, the Oghuz were possibly led by a core group of Toquz Oghuz clans or tribes. Likewise, Karluks and Oghuz Turks were distinct even though both were known as Turkmens in the 11th century; yet much later, Ilkhanate politician Rashid-al-Din Hamadani in his Jami' al-tawarikh mentions Karluks as of the Oghuz (Turkmen) tribes. Oghuz expansion by means of military campaigns went at least as far as the Volga River and Ural Mountains, but the geographic limits of their dominance fluctuated in the steppe areas extending north and west from the Aral Sea. Accounts of Arab geographers and travelers portray the Oghuz ethnic group as lacking centralized authority and being governed by a number of "kings" and "chieftains." Because of their disparate nature as a polity and the vastness of their domains, Oghuz tribes rarely acted in concert. Hence, by the late 10th century, the bonds of their confederation began to loosen. At that time, a clan leader named Seljuk founded a dynasty and the empire that bore his name on the basis of those Oghuz elements that had migrated southward into present-day Turkmenistan and Iran. The Seljuk Empire was centered in Persia, from which Oghuz groups spread into Azerbaijan and Anatolia. After the fall of Göktürk kingdom, Oghuz tribes migrated to the area of Transoxiana, in western Turkestan, in modern Kazakhstan and Kirghizstan. This land became known as the "Oghuz steppe" which is an area between the Caspian and Aral seas. Ibn al-Athir, an Arab historian, stated that the Oghuz Turks had come to Transoxiana in the period of the caliph Al-Mahdi in the years between 775 and 785. In the period of the Abbasid caliph Al-Ma'mun (813–833), the name Oghuz starts to appear in the Islamic historiography. By 780 AD, the eastern parts of the Syr Darya were ruled by the Karluk Turks and the western region (Oghuz steppe) was ruled by the Oghuz Turks. The