عبد الله بن ياسين
The death of the spiritual leader Abdallah ibn Yasin left the Almoravids under the sole command of Abu Bakr. Abu Bakr continued carrying out the Almoravid program without assuming the pretence of religious authority in himself. Abu Bakr, like later Almoravid rulers, took up the comparatively modest title of "amir al-Muslimin" ("Prince of the Muslims"), rather than the caliphal "amir al-Mu'minin" ("Commander of the Faithful").