linguistic:paraphrasing
Ribbed domes in Al-Andalus and the Maghreb

The Great Mosque of Córdoba in Al-Andalus was initially built with a system of double-arched arcades supporting the flat timberwork ceiling. The columns of the arcades are connected by horseshoe arches which support brick pillars, which are in turn interconnected by semicircular arches. This arcade system was copied during the mosque's subsequent expansions, but the expansion by al-Hakam II after 961 also introduced a series of ornate ribbed domes. Three domes span the vaults in front of the mihrab wall while another one covers an area now known by its Spanish name, the Capilla de Villaviciosa, located several bays before the mihrab. In sections which now supporting these domes, additional supporting structures were needed to bear the thrust of the cupolas. The architects solved this problem by the construction of intersecting arches. The domes themselves are built with eight intersecting stone ribs. Rather than meeting in the centre of the dome, the ribs intersect one another off-center, leaving the central space to be occupied by a smaller cupola. For the domes in front of the mihrab, the ribs form an eight-pointed star and an octagonal cupola in the centre. For the dome over the Capilla de Villaviciosa, the ribs leave a central square space between them, with an octagonal cupola added over this.

The ribbed domes of the Mosque-Cathedral of Córdoba served as models for later mosque buildings in the Islamic West of Al-Andalus and the Maghreb. At around 1000 AD, the Bab al-Mardum Mosque in Toledo was constructed with a similar, eight-ribbed dome, surrounded by eight other ribbed domes of varying design. Similar domes are also seen in the mosque building of the Aljafería of Zaragoza. The architectural form of the ribbed dome was further developed in the Maghreb: the central dome of the Great Mosque of Tlemcen, a masterpiece of the Almoravids founded in 1082, has twelve slender ribs, the shell between the ribs is filled with filigree stucco work.