In the 10th century, the Oghuz inhabited the steppe of the rivers Sari-su, Turgai and Emba north of Lake Balkhash in modern-day Kazakhstan.

[5] Others, harried by the Kipchak Turks, crossed the lower Danube and invaded the Balkans,[6] where they were stopped by a plague and became mercenaries for the Byzantine imperial forces (1065).

[9] In legend, the founder Osman's genealogy traces to Oghuz Khagan, the legendary ancient ancestor of Turkic people,[10] giving the Ottoman sultans primacy among Turkish monarchs.

He also observed that long separation had led to clear differences between the western Oghuz and Kipchak language and that of the eastern Turks.

[16] According to historians and linguists, the Proto-Turkic language originated in Central-East Asia,[17] potentially in Altai-Sayan region, Mongolia or Tuva.

[22][23][24] In early times, they practiced a Tengrist religion, erecting many carved wooden funerary statues surrounded by simple stone balbal monoliths and holding elaborate hunting and banqueting rituals.

[25] During the 2nd century BC, according to ancient Chinese sources, a steppe tribal confederation known as the Xiongnu and their allies, the Wusun (probably an Indo-European people) defeated the neighboring Indo-European-speaking Yuezhi and drove them out of western China and into Central Asia.

[31] Yury Zuev (1960) links the Oghuz to the Western Turkic tribe 姑蘇 Gūsū < (MC *kuo-suo) in the 8th-century encyclopaedia Tongdian[32] (or erroneously Shǐsū 始蘇 in the 11th century Zizhi Tongjian[33]).

Zuev also noted a parallel between two passages: Based on those sources, Zuev proposes that in the 8th century the Oghuzes were located outsides of the Ten Arrows' jurisdiction, west of the Altai Mountains, near lake Issyk-Kul, Talas river's basin and seemingly around the Syr Darya basin, and near the Chumul, Karluks, Qays, Quns, Śari, etc.

Ibn al-Athir, an Arab historian, claimed that the Oghuz Turks were settled mainly in Transoxiana, between the Caspian and Aral Seas, during the period of the caliph Al-Mahdi (after 775 AD).

Stone heads of Seljuq elites kept at the New York Metropolitan Museum of Art displayed East Asian features.

Ḥāfiẓ Tanīsh Mīr Muḥammad Bukhārī also related that the "Oghuz Turkic face did not remain as it was after their migration into Transoxiana and Iran".

The shelter of the Oghuz tribes was a tent-like dwelling, erected on wooden poles and covered with skin, felt, or hand-woven textiles, which is called a yurt.

Their cuisine included yahni (stew), kebabs, Toyga soup (meaning "wedding soup"), Kımız (a traditional drink of the Turks, made from fermented horse milk), Pekmez (a syrup made of boiled grape juice) and helva made with wheat starch or rice flour, tutmac (noodle soup), yufka (flattened bread), katmer (layered pastry), chorek (ring-shaped buns), bread, clotted cream, cheese, yogurt, milk and ayran (diluted yogurt beverage), as well as wine.

According to the Book of Dede Korkut, which demonstrates the culture of the Oghuz Turks, women were "expert horse riders, archers, and athletes".

In the 700s, the Oghuz Turks made a new home and domain for themselves in the area between the Caspian and Aral seas and the northwest part of Transoxania, along the Syr Darya river.

They had moved westward from the Altay mountains passing through the Siberian steppes and settled in this region, and also penetrated into southern Russia and the Volga from their bases in west China.

[55] In his accredited 11th-century treatise titled Diwan Lughat al-Turk, Karakhanid scholar Mahmud of Kashgar mentioned five Oghuz cities named Sabran, Sitkün, Qarnaq, Suğnaq, and Qaraçuq (the last of which was also known to Kashgari as Farab,[56] now Otrar; situated near the Karachuk mountains to its east).

Yörüks are an Oghuz ethnic group, some of whom are still semi-nomadic, primarily inhabiting the mountains of Anatolia and partly Balkan peninsula.

Rashid-al-Din and Abu al-Ghazi Bahadur added three more: Kïzïk, Karkïn, and Yaparlï, to the list in Jami' al-tawarikh (Compendium of Chronicles) and Shajare-i Türk (Genealogy of the Turks), respectively.

[66] According to Selçukname, Oghuz Khagan had 6 children (Sun – Gün, Moon – Ay, Star – Yıldız, Sky – Gök, Mountain – Dağ, Sea – Diŋiz), and all six would become Khans themselves, each leading four tribes.