According to Lane-Poole, Al-Ashraf Musa was a descendant of Saladin and the great grandson of Az-Zahir Ghazi, Amir of Aleppo, who had struggled against Al-Adil for supremacy in the Ayyubid domains.
For a brief period Shajar ad-Durr ruled as Sultana, but she was soon replaced by Izz ad-Din Aybak.
For this reason, they decided it would be prudent to have a nominal Ayyubid Sultan in power in Cairo, to give their rule a veneer of legitimacy.
In 1254, a new potential threat to Aybak's rule emerged when Faris ad-Din Aktai, leader of the Bahri Mamluks, asked permission to move into the citadel of Cairo with his future wife, who was the sister of the Ayyubid ruler al-Malik al-Mansour of Hama.
After this, Aybak resolved to rule on his own authority and decided he had no further need of a titular Ayyubid Sultan on whose behalf he claimed to act.