Partially Romanized and Christian during the Roman Empire, the Berbers and their lands were Islamized in the 7th century with the expansion of the Umayyad Empire from Syria. Previous Roman-Berber cities gradually began to become Arabo-Berber cities where an Arabo-Islamic culture was involved. Arabization was considered as a low phenomenon, mostly due to cultural and economical exchanges between the new Maghreb and the old Mashreq of the Arab world until the 12th century with the invasion of the Bedouin tribe Banu Hilal expanded their cultural influence towards the inland areas.