عبد الله بن ياسين
Ibn Yasin and Yahya collaborated in the leadership of this new movement - soon to be called "the Almoravids". Abdallah ibn Yasin was the religious imam and ideological leader of the movement, Yahya ibn Umar the overall military commander, and thus the first Almoravid emir. Chronicler Qadi Ayyad claims that Yahya ibn Umar was the first to use the title "amir al-muslimin" ("Prince of the Muslims"), that would thereafter be used by Almoravid rulers.