The Seljuks were a ruling familiy of the Ogus branch of the Turkish peoples who began settling in lands of the Abbasid caliphate, becoming Muslims, in the 10th century.

They established a local power, quickly expanded it and occupied Baghdad, capital of the caliphate, in 1055. They ruled most of the lands of the caliphate, under Abbasid suzerainty, with the title of sultan.

The empire split after the death of Nizam al-Mulk, but a branch remained as rulers of Anatolia (incorporated in the Muslim world by Seljuk conquest from the Byzantines) from the early 12th century until the Mongol conquest in the 13th century.