عبد الله بن ياسين
Abu Bakr ibn Umar was a member of the Banu Turgut, a clan of the Lamtuna Berbers. His brother, Yahya ibn Umar al-Lamtuni was the chieftain of the Lamtuna who, together with the Maliki teacher Abdallah ibn Yasin, launched the Almoravid ("murabitūn") movement in the early 1050s.