 A description of the city was given by Ibn Hawqal, a Baghdad merchant who visited Sicily in 950.A walled suburb called the Kasr (the citadel) was (and remains) the center of Palermo, and the great Friday mosque stood on the site of the later Roman cathedral.The suburb of Al-Khalisa (Kalsa) contained the sultan's palace, baths, a mosque, government offices, and a private prison.