Sultan Yūsuf ibn ʿAbd al-Muʾmin ibn ʿAlī al-Qaysī.
His mother was a Byzantine (Rūmiyya) woman named Zahr.
He assumed dominion over the realm by virtue of an earlier writ of investiture from his father.
He was blond, light-eyed, smooth-cheeked and handsome; a man of few words and lowered gaze, courageous and awe-inspiring, far-sighted, forbearing, and reluctant to shed blood. A slight lisp marked his speech, he was thought to be tight-fisted, and he had several children.
He first appointed Abū Zayd ibn Yūjān as vizier, later dismissed him and appointed his brother, Prince Ibrāhīm. His confidential correspondence was handled by Ibn ʿAyyāsh and Ibn Yakhliftan al-Fāzāzī, while more than one jurist successively held his chief judgeship.
Ibn Ghāniya waged war against him and seized Fez.
In the Far Sūs, Yaḥyā ibn al-Jazzārah rebelled; his power swelled, he defeated the Almohads several times and nearly conquered the Maghrib, but he was killed. His sobriquet was Abū Qaṣabah.
In 601 AH the sultan marched out, besieged al-Mahdiyya for several months, and took it under a pledge of safety granted to Ibn Ghāniya’s deputies. Ibn Ghāniya’s brother Sīr defected to the sultan, who treated him with honour.
ʿAbd al-Wāḥid ibn ʿAlī states in his History (1): “I was informed that Abū ʿAbd Allāh spent, on this expedition, a total of one hundred and twenty loads of gold. He returned to Marrakesh in 604 AH. When the truce with the Franks expired, the sultan crossed with his armies to Seville (2).”
Then (3), in 608 AH, he set out once more to wage jihad against the enemy and laid siege to one of their fortresses,