The Sidi Belahcen Mosque was founded in 1296 by the Zayyanid sultan Othman ibn Yaghmorasen as the burial-place of the Sufi master Abu al-Hasan al-Tlemceni. The building is small but architecturally exceptional — a square prayer hall, a single ribbed cupola of pierced stucco, and a mihrab framed by some of the finest carved-plaster decoration in the city.
Deconsecrated under French rule, it now houses the small Museum of Islamic Art — manuscripts, ceramics, jewellery, and architectural fragments — and is one of the easiest places in Tlemcen to study Zayyanid plaster and tile work close up. Forty minutes. The label English is partial but the building speaks for itself.