Aibak was born in c. 1150. His name is variously transliterated as "Qutb al-Din Aybeg", "Qutbuddin Aibek", and "Kutb Al-Din Aybak". He came from Turkestan, and belonged to a Turkic tribe called Aibak. The word "Aibak", also transliterated as "Aibak" or "Aybeg", derives from the Turkic words for "moon" ("ai") and "lord" ("bek"). As a child, he was separated from his family, and taken to the slave market of Nishapur. There, Qazi Fakhruddin Abdul Aziz Kufi, a descendant of the noted Muslim theologian Abu Hanifa, purchased him. Aibak was treated affectionately in the Qazi's household, and was educated with the Qazi's sons. He learned archery and horse-riding, besides Quran recital.