The Musjid was founded by the Almoravid emir Yusuf ibn Tashfin in 1082 when he founded the city of Tagrart (present-day Tlemcen), an extension of the earlier Idrisid-era city of Agadir. However, the Musjid was restored and decorated by his son and successor, Ali ibn Yussef. Among others, the famous dome near the mihrab of the Musjid dates from this renovation, an inscription under the dome indicating that it was completed in 1136. Curiously, however, the current name of the emir was deleted from the inscription, perhaps by the Almohads who governed the city after the Almoravids. It is also believed that the old Almoravid palace of the city, the Qasr al-Qadima or Qasr al-Bali (“Old Palace”), directly adjoined the Musjid on its northwest side.

The miḥrāb is unusually ornate, surrounded by multilobed arches decorated with arabesques. The work is indicative of trends that were to develop in Spain and North Africa under the Almoravids’ successors, the Almohads and the Naṣrids.

The Great Musjid of Tlemcen (Arabic: المسجد الكبير بتلمسان) was built in 1136 by Ali Ben Youssef, caliph of the Berber dynasty of the Almoravids, and its minaret in 1236 by Sultan Zianide Yghomracen Ibn Zyan. It is built of stone, brick and plaster.