Abu Ya`qub Yusuf or Yusuf I (Arabic: أبو يعقوب يوسف‎‎ Abū Ya‘qūb Yūsuf; 1135 – 14 October 1184) was the second Almohad Amir or caliph. He reigned from 1163 until 1184 in Marrakech. He had the Giralda in Seville built as well as Koutoubia in Marrakech and Hassan Tower in Rabat.

Yusuf was the son of Abd al-Mu'min, the first caliph of the Almohad dynasty. Originally hailing from North Africa, Yusuf and his bloodline were descended from the Zenata Berbers. Like a number of Almohad rulers, Yusuf favored the Zahirite or literalist school of Muslim jurisprudence and was a religious scholar in his own right. He was said to have memorized Sahih Bukhari and Sahih Muslim, two collections of the prophet Muhammad's statements considered canonical in Sunni Islam, by heart, and was a patron of the theologians of his era. Respected men of letters such as Ibn Rushd and Ibn Tufayl were entertained at his court. Yusuf favored Cordoban polymath Ibn Maḍāʾ as his chief judge; during the Almohad reforms, the two oversaw the banning of any religious material written by non-Zahirites. Yusuf's son al-Mansur would eventually take the reforms even further, actually burning non-Zahirite books instead of merely banning them.

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