Regardless of the political importance of the Almoravids, which was very closely linked to the personality of Yusuf ibn Tashfin (1060-1106), only a small number of buildings from their era have survived. The foundation of the Great Mosque of Tlemcen (1082) demonstrably dates back to that period, even though it underwent substantial alterations under his son and successor Ali ibn Yusuf (1106-1143). The town Tlemcen was founded in the eighth century on the ruins of the Roman city of Pomaria although it did not rise to prominence until the Almoravids period in the eleventh century. Since 1980's the city was known as Tilimsen - It lies near the Moroccan border. Tlemcen is backed by the cliffs of the well-watered Tlemcen Mountains and overlooks the fertile Hennaya and Maghnia plains.

Today, the Mosque is situated beside a splendid boulevard, with an eye catching minaret, whose facades are richly decorated. Immediately next to the minaret lies the entrance to the mosque courtyard, which is surrounded on all sides by arcades and where the visitor is tempted to linger in its stillness. In the prayer hall the central aisle leading to the mihrab is somewhat wider than the other side aisles. This emphasis on the central aisle serves primarily to direct the eye towards the mihrab, which gives the direction of prayer to Mecca and thus constitutes the most important element of the mosque.

By the time the Great Mosque of Cordoba, the most important mosque in western Islam, was built (785/786), the concept of emphasizing the central aisle to the mihrab through its width and decoration was already well established, and so the "oriented" mosque, which became obligatory for all later mosques in both Andalusia and Morocco, came into being. The mihrab of the Great Mosque of Tlemcen is in fact inspired by on that of the Great Mosque of Cordoba (in Al-Hakam II's extension of 962-966), with its horseshoe-shaped opening and its polygonal niche.

The mihrab facade also takes after the same model, with its central horseshoe arches, a rectangular alfiz frame, a decorative frieze to finish it off, and an arcade suggested by the use of false arches, even though stucco alone was used for decoration in Tlemcen. The vegetal shapes here, however, are smaller and more delicate, as is the case with comparable works for the caliph in Cordoba, and, moreover, they are carved in a rich variety of forms. The great dome above the area before the mihrab, which also quite specifically emphasizes the location of the mihrab area, is another parallel with the Great Mosque of Cordoba. Another dome at the height of the second span of the central aisle serves the same purpose, accentuating the longitudinal axis of the mosque oriented towards the mihrab. While the area before the mihrab in the Great Mosque of Cordoba (in Al-Hakam II's extension) is vaulted with a large dome decorated with gold mosaic, in Tlemcen there is a somewhat higher ribbed dome, covered with stucco.

The ribs of this dome intersect, forming areas filled with openwork stucco decoration, whose vegetal ornamentation shows a clearly Andalusian influence. The fine leaf and flower paintings are reminiscent of comparable motifs on the stucco panels of the "Aljaferia of Saragossa" (1049/50-1082/83), that famous palace which, with its outstanding artistic decoration, is an exceptional example of 11th century Spanish taifia's art. The building of the Aljaferia of Saragossa was completed at roughly the time when work on the Great Mosque of Tlemcen was begun. As a result of this we can suppose that Andalusian artists moved into Morocco after the local taifia's courts could offer them no further appropriate commissions. This way Spanish-Islamic art forms were conveyed to Morocco, where they met with an immediate echo in Almoravids art.