The Juyushi Mosque (Arabic: الجامع الجيوشى, lit. ’Mosque of the Armies’) is a historic monument in Cairo, Egypt. The mosque is dated to 1085 CE, during reign of the Fatimid Imam-Caliph al-Mustansir Billah. Its construction was sponsored by Badr al-Jamali, the vizier of al-Mustansir, who was Amir al-Juyush (Arabic: امير الجيوش, lit. ’Commander of the Armies’). It is located on the Muqattam hills above the Southern Cemetery of Cairo.

The building’s construction is dated by an Arabic foundation inscription to 1085, during the Fatimid period and the reign of al-Mustansir Billah. The inscription identifies the structure as a mashhad (Arabic: مشهد, lit. ’shrine’), meaning a commemorative shrine or mausoleum. It is not clear whom the mashhad commemorates or what its exact function was. The most plausible theory is that the monument commemorates the victories of Badr al-Jamali, the powerful Fatimid vizier whose title, Amir al-Juyush (“Commander of the Armies”), is invoked in the foundation inscription. Badr al-Jamali himself was not buried here, but rather in a tomb outside Bab al-Nasr, according to al-Maqrizi. The structure’s isolated setting on the Muqattam hills above Cairo is also unusual and has even led to one scholarly theory suggesting it was actually a watchtower disguised as a mosque.

In 1731–2, during the Ottoman period, the building was restored and some painted decoration was added to the interior. In the 1990s the mosque underwent a major renovation organized and funded by the Dawoodi Bohra community, who restored several other Fatimid-era mosques in Cairo around this time. The Dawoodi Bohra community, led by Mohammad Burhanuddin, reconstructed the mosque after conducting research on the building. During the restoration, architectural components from other Fatimid temples in Egypt served as a guide for what to put where. Some historical details, including Ottoman decoration, were eliminated during the restoration. As of 2018, the mosque was situated inside a military zone and was not open to visitors without special permission.

The building, often described as a mosque, is the most complete mashhad (commemorative shrine) to survive from the Fatimid period. It is centered around a small courtyard, which is entered from the outside through a plain door and passage. On one side of the courtyard is the prayer hall or sanctuary, while opposite this, standing on the central axis of the building, is a minaret. On the other two sides of the courtyard are rooms, as well as a passage leading to a small domed room projecting from the rest of the building. Small rooms also flank the minaret.

The prayer hall is entered from the courtyard via a large keel arch flanked by two smaller arches with supporting columns, an arrangement that recurs in Fatimid architecture. Beyond this is a rectangular space covered by cross-vaults, followed by a roughly square area covered by a dome, flanked by two more spaces each covered by a cross-vault. The dome rests on an octagonal base with four plain squinches.

The mihrab, which is framed by a panel of alternate bands of Qur’anic inscriptions and arabesque leaf patterns, all in carved stucco, is a prominent element of the interior. According to Oleg Grabar, this mashhad served as a triumph monument honoring Badr’s efforts to reinstate order for Caliph al-Mustansir. Others have reinterpreted this building as a fortified watch-post strategically positioned at the edge of the capital and dressed as a small mosque due to the appearance on the roof of domed edicules too small for any religious purpose and the exaggerated size of the minaret for an underpopulated area like al-Muqattam.

It is a rectangular, symmetrical building made of brick, masonry, and rubble. The vestibule of the entrance leads to a small courtyard that is bordered on both sides by vaulted chambers that may have been built for domestic use because they lack access to the prayer hall. A triple-arched portico on its courtyard side defines a transitional cross-vaulted vestibule that leads to the square dome chamber and two cross-vaulted extensions to the right and left. Despite being designated as a “mashhad” in accordance with its inscription, it is unknown who is buried in this mysterious building.

The oldest tower still standing in Egypt that is related to a building other than a congregational mosque is the minaret over the main entrance. It features the earliest muqarnas cornice still in use in Egypt, which is used to emphasize the visual distinction of the minaret’s many components. It has been argued that this Persian theme was transferred into Egypt through Armenian and Syrian mediation as the second instance of this muqarnas feature in Egypt—on the wall of Cairo close to Bab al-Futuh—is also linked to the Armenian vizier and former governor of Syria, Badr al-Jamali. It is also thought that Syrian design influences can be seen in the square shaft of the minaret.