Berbers (or Amazigh) are the indigenous ethnic group that inhabited most of North Africa before the Arab invasions in the tenth and eleventh centuries. The Arabs forcibly converted them to Islam, to refuse meant death. A large number of Judaized and Christianized Berbers fled across the Sahara desert to northern Nigeria, where they established a refuge, until they too were overtaken by the Arab Muslims and northern Nigeria became a Muslim area of the Hausa people.
The Berbers have their own language and culture and much of it survives in Morocco and Algeria, particularly in the Atlas Mountain area, where many Berbers fled from the Arab invasions. Most of the people of N. Africa (in Arabic called the Maghreb or West) think of themselves as Arabs, but in fact they are not, they are mostly Berber and other so-called Hamitic peoples, including the famous Tuaregs of the Sahara desert, who preexisted the Arab Muslim colonial conquests. There are estimated to be about 35 million Berbers, stretching from Morocco to Libya.
While the culture of the Berbers has significantly influenced the so-called Arab culture of Morocco and Algeria, until very recently their culture, including its language and art were officially forbidden, much as the Kurdish language and culture was suppressed in Turkey. After years of protests and much persecution the Berber language was recognized as an official language in Algeria in 2001 and in Morocco as recently as 2011. The Berbers are at pains to emphasize that they are not anti-Muslim, they are Muslims themselves, but they insist that they should be allowed to live their lives as Berbers without Arab interference (this is another article on minorities in the Arab world).