Tlemcen (tlĕmsĕnˈ) [key], city (1998 pop. 155,162), NW Algeria, capital of Tlemcen prov. Its location on a crossroads between the Mediterranean coast and the Sahara and between Algeria and Morocco has made it a commercial center since ancient times. Its prime importance was as a trade center during the Middle Ages. It flourished (13th–15th cent.) as the capital of a Muslim Berber dynasty, which ruled over much of what is now Algeria. Tlemcen has numerous splendid mosques and retains the atmosphere of medieval Muslim life. It still exports the carpets, woolens, and leather goods for which it has long been noted.