Sa'd ibn Ubadah
Muhammad ibn Yusuf was born in 1195 in the town of Arjona, then a small frontier Muslim town south of the Guadalquivir, now in Spain's province of Jaén. He came from a humble background and, in the words of the Castilian "First General Chronicle", initially he had "no other occupation than following the oxen and the plough". His clan was known as the Banu Nasr or the Banu al-Ahmar. According to later Granadan historian and vizier Ibn al-Khatib, the clan was descended from a prominent companion of the Islamic prophet Muhammad known as Sa'd ibn Ubadah of the Banu Khazraj tribe; Sa'd's descendants migrated to Spain and settled in Arjona as farmers. During his early life he became known for his leadership activity on the frontiers and for his ascetic image, which he maintained even after becoming ruler.