The Aghlabids were major builders and a relatively large number of early Islamic monuments built under their patronage have survived.

[6] The Great Mosque of Sousse was commissioned by the Aghlabid amir (ruler) Abu'l-Abbas Muhammad I in 851.

[6] The portico in front of the prayer hall, on the south side of the courtyard, was added in the 11th century under the Zirid dynasty, who also restored or decorated the mihrab (niche in the southern wall symbolizing the qibla) and the domed tower-pavilion at the northeast corner.

[8]: 24 [9] It is adjacent to the older Ribat of Sousse, which influenced the mosque's fortified appearance with crenellated walls and corner towers.

[3] A long Kufic Arabic inscription runs in a cornice along the top edge of the walls around the courtyard, containing most Qur'anic excerpts.

[6][9] At the mosque's northeast corner is a cylindrical bastion topped by a domed octagonal pavilion, which was likely a sawma'a, a space at roof level where the muezzin could issue the call to prayer, serving the function that minarets did in later periods.