The small mausoleum located opposite the Khanqah of Baybars al-Jashankir was accessed in the early 20th c., when it was described by K.A.C. Creswell, from the back of a carpenter's shop, into which part of its dome and zone of transition projected. The rise in the ground level had left the mausoleum partially buried, so that the sills of the windows in the zone of transition were only about a meter above the floor of the shop.

The mausoleum was constructed of brick, was square in plan, and had a dome on pendentives and a partially ruined mihrab. The dome was smooth on both the interior, where it was coated with plaster, and on the exterior, which was only partially visible. The Qur'anic verse that begins "It is He who inhabits the mosques. . ."(XIX, 9) circles the base of the dome in Kufic inscription.

Source:
Creswell, K. A. C. 1978. The Muslim Architecture of Egypt. 2 vols. (NY: Hacker), p. 227-228.