 Ala al-Din Atsiz was the son Ala al-Din Husayn, who died in 1161.At the death of Ala al-Din Husayn, Atsiz was very young and the succession passed to his brother Sayf al-Din Muhammad, who shortly died in 1163, and was succeeded by his cousin Ghiyath al-Din Muhammad.When Atsiz became an adult, he began serving Ghiyath and the latter's brother Mu'izz al-Din Muhammad.