On 6 August 711, Lisbon was taken by Muslim forces. These conquerors, who were mostly Berbers and Arabs from North Africa and the Middle East, built many mosques and houses, rebuilt the city wall (known as the ''Cerca Moura'') and established administrative control, while permitting the diverse population (Muwallad, Mozarabs, Berbers, Arabs, Jews, ''Zanj'' and ''Saqaliba'') to maintain their socio-cultural lifestyles. Mozarabic was the native language spoken by most of the Christian population although Arabic was widely known as spoken by all religious communities. Islam was the official religion practised by the Arabs, Berbers, Zanj, Saqaliba and Muwallad (muwalladun).