[3] The Fatimid dynasty were Isma'ili Shi'a Muslims claiming descent from the Islamic prophet Muhammad, and the mosque was originally built to be the resting place of the head of Husayn, the son of Muhammad's cousin and son-in-law Ali, who was slain at the Battle of Karbala in 680 and is revered as a martyr by Shi'as.

At this time bronze facings in the Mamluk style were added to the original main doors which had been carved in wood.

Today the doors are replaced by replicas while the originals, featuring both the Mamluk bronze-faced and Fatimid wood-carved facades, are on display at Cairo's Museum of Islamic Art.

[3] The Mamluk restoration also added wooden mashrabiyya screens to the portico fronting the mosque, as still visible today.

[5] As mentioned above, the wooden doors at the entrance of the mosque today are replicas of the originals, now in the Museum of Islamic Art.

At both ends of the northwest wall are chamfered corners with muqarnas, a feature that had previously been used at the al-Aqmar Mosque (late 11th century).

Many of the Kufic inscriptions around the arches have now disappeared, but the remaining examples in the prayer hall demonstrate a very ornate late-Fatimid style in which the letters are carved against a background of vegetal arabesques.

[5] Some of the original stucco window grilles have survived in situ and some have been moved to the Museum of Islamic Art in Cairo.