عبد الله بن ياسين
In order to ensure they did not lose Sijilmassa again, Abu Bakr launched a campaign to secure the roads and valleys of southern Morocco. He immediately captured the Draa valley, then moved along the Wadi Nul (along the edge of the Anti-Atlas, picking up the adherence of the Sanhaja tribes of the Lamta and the Gazzula (Jazzula) to the Almoravid movement. Abu Bakr led the conquest of the Sous valley of southern Morocco, seizing the local capital of Taroudannt in 1057. By negotiation, Abdallah ibn Yasin secured an alliance with the Masmuda Berbers of the High Atlas, which allowed the Almoravids to cross the mountain range with little incident and seize the critical Zenata-ruled citadel of Aghmat in 1058 with little opposition. Delighted at the apparent ease of their advance, Abdallah ibn Yasin ventured into the lands of the Berghwata of western Morocco with only a light escort and was promptly killed. Abu Bakr, who was then mopping up the area north of Aghmat, wheeled the Almoravid army around and conquered the Berghwata in a brutal campaign of revenge.