A separate significant division of the Karluks are the Chigils, a tribe that had detached from the Karluk.

They reside around Issyk Kul.

The diverse population adheres to a spectrum of religious beliefs.

The Karluks and the majority of the Turkic population profess Tengrianism, considered as shamanism and heathen by the Christians and Muslims.

Chigils are Christians of the Nestorian denomination.

The majority of the Toquz Oghuz, with their khan, are Manicheans, but there are also Christians, Buddhists, and Muslims among them.

The peaceful penetration of Muslim culture through commercial relations plays a far more important role in their conversion than Muslim arms.

The merchants are followed by missionaries of various creeds, including Nestorian Christians.

Many Turkestan towns have Christian churches.

The Turks hold sacred the Qastek pass mountains, believing to be an abode of the deity.

Each creed carries its script, including Türkic runiform, Sogdian, Syriac, and later the Uyghur.