Beni Ḥassān
Beni Ḥassan ( "Children of Ḥassān") is a nomadic group of Arabian origin, one of the four sub-tribes of the Maqil Arab tribes who emigrated in the 10th century to the Maghreb with the Bani Hilal and Banu Sulaym tribes. In Morocco, they first settled, alongside their Maqil relatives, in the area between Tadla and the Moulouya River. The Sous Almohad governor called upon them for help against a rebellion in the Sous, and they resettled in and around that region. They later moved to Mauritania, and from the 16th century onwards, they managed to push back all  black Mauritanians southwards to the Senegal Valley river. The Beni Hassan and other warrior Arab tribes dominated the Sanhaja Berber tribes of the area after the Char Bouba war of the 17th century. As a result, Arabian culture and language came to dominate, and the Berber tribes underwent some Arabisation. The Bani Hassan dialect of Arabic became used in the region and is still spoken, in the form of Hassaniya Arabic. The hierarchy established by the Beni Hassan tribe gave Mauritania much of its sociological character. That ideology has led to oppression, discrimination and even enslavement of other groups in  Mauritania. In Western Sahara, unlike other areas where they mixed with Berbers, their descendants are considered among the clean-blooded Arab tribes. Beni Hassan sub-tribes. Several other Arab tribes joined the Maqils and became part of the Beni Hassan tribe.