The mosque of al-Salih Tala'i', built by the Fatimid vizier al-Salih Tala'i' ibn Ruzzik in 1160 during the caliphate of al-Fa'iz, is the second oldest existing Fatimid mosque to be built by a vizier, the first being that of al-Aqmar, and represents the last Fatimid mosque in Cairo. It is also the second of the "suspended" or hanging mosques (after that of al-Aqmar). It sits just across from and facing Bab (Gate) Zuwayla north of the Citadel. Just behind this mosque is the tent maker's market. This early mosque's simplicity provides a charm which fortunately, its restoration has done much to preserve. 

A suspended mosque is one that sits above shops that comprise part of the religious structure's endowment, or waqf, helping to pay for the building's upkeep and the employment of its personnel. Located below the current ground level, they provide an indication of this mosque's antiquity for when the mosque was built some 800 years ago, they were at street level. Originally there were seven shops in the front with twelve more on each side, but none on the qibla wall which has beautiful windows decorated with stained glass and stucco work.

Originally, this mosque was conceived of as a shrine (mashhad) to house the head of al-Husayn, which was brought to Cairo from its shrine in Ascalon by the vizier when it was threatened by an impending attack from the Crusaders. But the caliph instead kept the relic in a shrine in the Fatimid palace, which became part of the Mosque of al-Husayn when the palace was destroyed.

Interestingly, of the five Fatimid period mosques in Cairo, this is one of only two that was originally built with minarets (the other being the Mosque of al-Hakim). Bother were originally located outside the city walls of Cairo. Some scholars believe that the other Fatimid mosques were built without minarets as a deliberate political statement against the Abbasids who they ejected from Egypt, and whose imperial mosque architecture featured very conspicuous minarets. 

The mosque's intended use as a shrine for a Shi'i martyr may account for the introduction of an entrance portico consisting of five keel arches, which is a feature unique among mosques in Cairo. The style of the these arches that are ribbed and cusped and surmount classical pillars, seems to follow that of the al-Aqmar mosque, however. The mashrabiyya screens on the porch of the entrance were added to the mosque after it was restored following the damage caused ot the structure by a terrible earthquake in 1303. The carving on the inner side of the wooden door of the main entrance is a 1935 replica of the original door, which was moved to the Museum of Arab Art between 1887 and 1899. However, the outside of the door is faced with geometrically decorated bronze plates which date to the 1303 restoration. This plating may be the earliest occurrence of such a technique in Islamic Egypt. 

The interior plan is that of a congregational mosque, with its large central courtyard. The prayer hall consists of three aisles which run parallel to the qibla wall. The three other sides of the courtyard have one aisle each. The exterior walls are built of stone while the interior arcades are formed by brick keel arches carried on columns. No two of the column capitals are the same and all are reused from pre-Islamic Christian buildings. 

The arches are framed by a continuous band of Qur'anic verses executed in a floriated Kufic script (Kufic script on an arabesque background). This type of inscription was common during the Fatimid period. The arches display wooden tie beams, which still show their original carving. Similar carving can also be seen on the wooden tabliyyas or impost blocks between the arches and the column capitals.

The wooden minbar was added by the Mamluk Amir Baktimur al-Jukandar in 1300, and is the second oldest existing Mamluk minbar in Cairo after that of Husam al-Din Lajin built for the Mosque of Ibn Tulun in 1296. Its decoration is a geometric repeating pattern based on star shapes with polychrome accents. The minbar was restored in the early twentieth century, and again only very recently.

Behind the pulpit is a rectangular opening framed by stucco ornament and closed by a bronze grille. This opening is the termination of a rectangular vertical shaft which runs upwards in the thickness of the wall to the roof, where it was once covered by a hood with a sloping roof. Its sides were closed except the one facing north, which traps the prevailing breeze and deflects it downwards. This is the earliest existing example of a malqaf (wind scoop) in Cairo. 

The Mosque of al-Salih Tala'i is one of about 43 historic monuments that were marked for restoration in the first phase of a project meant to turn the medieval part of Cairo into an open-air museum. However, before any archaeological work could begin, a trench surrounding the mosque had to be drained of the water accumulated from broken sewage pipes or leaking taps. The sewage system, installed at the end of the last century, did not take into consideration the depth of the foundations of the monuments. This work has been completed, as well as most of the remaining restoration to the building and its interior elements.

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