Muhammad I of Khwarazm in the context of "Berkyaruk"

The Anushtegin dynasty or Anushteginids (English: /ænuʃtəˈɡinid/, Persian: خاندان انوشتکین), also known as the Khwarazmian dynasty (Persian: خوارزمشاهیان) was a Sunni Muslim dynasty of Turkic mamluk origin from the Bekdili clan of the Oghuz Turks. The Anushteginid dynasty ruled the Khwarazmian Empire, consisting in large parts of present-day Central Asia, Afghanistan and Iran in the approximate period of 1077 to 1231, first as vassals of the Seljuks and the Qara Khitai (Western Liao), and later as independent rulers, up until the Mongol conquest of the Khwarazmian Empire in the 13th century.

The dynasty was founded by commander Anushtegin Gharchai, a former Turkic slave of the Seljuq sultans, who was appointed as governor of Khwarazm. His son, Qutb ad-Din Muhammad I, became the first hereditary Shah of Khwarazm. Anush Tigin may have belonged to either the Begdili tribe of the Oghuz Turks or to Chigil, Khalaj, Qipchaq, Qangly, or Uyghurs.

Ala al-Din wa-l-Dawla Abu'l-Muzaffar Atsiz ibn Muhammad ibn Anushtegin (Persian: علاءالدين و الدوله ابوالمظفر اتسز بن محمد بن انوشتگین; 1098 – 1156), better known as Atsiz (اتسز) was the second Khwarazmshah from 1127 to 1156. He was the son and successor of Muhammad I.