The Slat al-Fassiyine Synagogue was one of the few synagogues where the non-Sephardic rituals of the toshavim continued up until the 20th century.

History
Slat al-Fassiyin is reputed to be the oldest synagogue of the Mellah of Fez and one of the oldest in continuous use. It is thought to have been built during the Marinid period.

Its current building dates from the 17th century. In 1791–92, Moulay Yazid expelled the Jews from the Mellah and turned Slat al Fassiyine into a prison. However, after a short period, he allowed them to go back.