The twin port cities of Rabat (Ar. Ribāṭ, Ribāṭ al-Fatḥ; Mor. Ar. r-Rbāṭ) and Salé (Ar. Salā; Mor. Ar. Slā), on Morocco’s Atlantic coast, lie on the southern and northern banks, respectively, of the Bou Regreg River (Ar. Wādī Abū Raqraq). The area around the Bou Regreg was populated in ancient times, and Muslim historians report that Jews and Christians were living in the region before the advent of Islam. In the twelfth century the Almohad sultan ʿAbd al-Muʾmin and his successors planned to make Rabat their capital city and began constructio…