The Mosque was built by Bata'i, during the seventh Fatimids ruler of Egypt in 519H. (1125). It plan, not unlike previous ones, consists of an open Sahn (The interior courtyard of a Mosque), 10 square meter surrounded by four Riwaqs (The arched chambers around a Sahn or courtyard within a mosque), the largest being the sanctuary. The Sahn has four square piers at the corners.

The arches, which are supported on marble columns, are of the keel type which did not appear in Egypt until the latter part of the Fatimids period, and was first seen in the dome of Sheikh Yunis, attributed to Bader al Gamali. A beautiful band of Kufic runs round each arch. The spandrels are decorated with shallow saucers composed of eight ribs radiating from a central medallion. The four Riwaqs are roofed with shallow domes; the back aisle, however, has a flat wooden ceiling.

The Minbar and the minaret were among the parts restored by Yalbugha al Salami, during the reign of Sultan al Zahir Barquq, in 799H. (1396/97). A dating inscription to this effect is fixed over the mihrab. The Minbar still retains its Fatimids ornament, which may be observed on the entrance arch and at the back of the speaker's seat. Other Fatimids ornament may be observed in some panels in the built- in cupboards and the lining of the door soffits.

The chief glory of this mosque lies in its façade which presents an ambitious architectural scheme, of good proportions, with a great variety of ornament. The architect had to take into consideration the direction of the Qibla, when designing the interior of the mosque, whereas the façade follows the alignment of the street, so it is not parallel to the Qibla wall. The space which might otherwise have been wasted was occupied by the vestibule, the staircase and two rooms opening into the interior. This treatment, conforming to the street alignment externally and to the correct Qibla direction internally, was introduced for the first time in this mosque; it was later on invariably applied in the design of all the Madras's of the Mamluks period.

The only part of the facade that is exposed consists of the entrance and the left wing, the right wing being hidden by a later house. The entrance, slightly set forward, is in the centre of the façade. The entrance door- way has a fine joggled lintel and is covered by a beautiful fluted hood: the first flutes run horizontally right across, while the rest radiate from the medallion which occupies the back of the hood. The centre of this medallion is decorated with the two words Muhammad and 'Ali in Kufic, pierced right through the stone; then comes a circle of arabesque and another of pierced Kufic, and finally a band decorated with interlacing scrolls. The work of engraving and piercing shows skill and perfection. The niches on either side of the entrance are each crowned with four tiers of stalactites; set back within these, are two smaller ones, each having a small fluted semi- dome. Above these two niches are two smaller ones, each having a fluted hood, supported by two engaged columns. The stalactites present the first introduction of this element into the design of a façade.

The left wing is relieved by a slightly recessed panel, covered by a very shallow fluted hood, similar to that over the main entrance. On both sides are two lozenge panels and above each is another panel; all these are decorated in various designs. Three bands of decorative Kufic run across the façade. The first, at the summit, contains the name of Al Amir Bi-Ahkam-Allah and next to it is the name of his Wazir (Minister) al- Ma'mun al- Bata'ihi, together with his titles, and the date of foundation. The second runs at the springing of the entrance arch; this too contains the names of al- Ma'mun and his titles and the date of foundation. This fashion, the combination between the names and titles of the Khalifa (Ruler) and Wazir, shows what influence the Ministers of State had attained towards the end of the Fatimids period. The third band runs at the level of the door lintel and only contains verses from the Quran.