Kairouan (al-Qairawan, القيروان) was founded in 670/50 AH by 'Uqba ibn Nafi, the Arab general in command of the Muslim conquest of North Africa. The principal monument in the city is the Great Mosque, also known as the mosque of Sidi 'Uqba after the general who founded it. The first mosque on the site was begun immediately after the Arab conquest and consisted of a square enclosure containing a courtyard and prayer hall or sanctuary. This first building was made of mud brick and had to be restored in 695. There was another major reconstruction in 724-43 when a minaret was added. The present minaret was added by the Aghlabids in 836. It is a giant three-tier structure built of baked bricks on a base of reused ashlar blocks. At present, the minaret stands on the north wall of the courtyard but in the ninth century, it would have been outside the mosque courtyard in a manner similar to the contemporary Abbasid mosques of Samarra.
The mosque took its present form from the major rebuilding which took place under the Aghlabids which was completed in 862. The present mosque enclosure forms a large rectangle measuring 125 by 85 m. The prayer hall is one-third of the mosque area and comprises seventeen aisles perpendicular to the qibla wall with another aisle parallel to the wall. Aghlabid modifications included the present mihrab, the dome in front of the mihrab and the minbar. The mihrab niche is lined with perforated marble panels decorated with vegetal designs. Surrounding the mihrab are a series of polychrome lustre tiles which are believed to have been imported from Baghdad. The dome covering the area in front of the mihrab is built of stone and rests on a drum supported by large shell-shaped squinches. The dome has a gadrooned form which internally takes the form of thin radiating ribs. The inside of the drum is circular and decorated with a series of sixteen blind niches and eight arched windows. The minbar is the oldest in existence and consists of a high staircase with a series of intricately carved panels on the side decorated with geometric and stylized vegetal designs. The present maqsura (screen) was added in restorations of the eleventh century. Further restorations were carried out in 1294 when the arches of the arcades were remodeled and the projecting portal of Bab Lalla Rayhana was added. Other Aghlabid monuments at Qairawan include the Mosque of the Three Gates, and the famous polygonal cisterns or artificial lakes. Outside Qairawan three satellite cities were established known as al-Abbasiya, Raqqada and Sabra al-Mansuriyya. Nothing remains of Abasiyya, although at Raqqada there are huge reservoirs and the remains of a large palace built of baked brick. Other cities with Aghlabid monuments include Tunis, Susa, Sfax and Monastir. In 1052 the city was enclosed with a crenellated brick wall which was extensively restored in the eighteenth century.