 Yusuf ibn Tashfin (c. 1061–1106) was the Berber Almoravid ruler in North Africa and Al-Andalus (Moorish Iberia).He took the title of "amir al-muslimin" ("commander of the Muslims") after visiting the Caliph of Baghdad ""amir al-Mu'minin"" ("commander of the faithful") and officially receiving his support.He was either a cousin or nephew of Abu Bakr ibn Umar, the founder of the Almoravid dynasty.