يوسف بن تاشفين
Nevertheless, the family was still subject to taxation by the King of Castile, to whom they were vassals. The drain of these taxes effectively weakened the kingdom's power: al-Mu'tamid's decision to stop paying these taxes caused King Alfonso VI of Castile (who had already conquered Toledo in 1085) to besiege Seville. Al-Mu'tamid asked help from the Berber Almoravids of Morocco against the Castilian king. Al-Mu'tamid supported the Almoravid ruler Yusuf ibn Tashfin against Alfonso in the Battle of Sagrajas in 1086. The Moroccans established themselves at Algeciras and, after defeating the Christians, occupied all the Islamic taifas, including Seville itself in 1091. After they ravaged the city, al-Mu'tamid ordered his sons to surrender the royal fortress (the early Alcázar of Seville) in order to save their lives. When his son, Rashid, had advised him not to call on Yusuf ibn Tashfin, Al-Mu'tamid had rebuffed him: