Yaḥyā ibn Ibrāhīm appears as the chief of the Juddāla at the beginning of the movement’s formative phase. In 427 A.H., corresponding to 1035/6, he set out on pilgrimage. Returning from Mecca, he visited Qayrawān, where he met Abū ʿImrān al-Fāsī, a leading exponent of the Mālikī school of law.

The conversation convinced Yaḥyā that Islam among his people was weak and superficial. He therefore sought a scholar willing to teach in the Sahara. Abū ʿImrān could not find a disciple ready to face the desert’s hardships, but he directed Yaḥyā to his former student Wajāǧ ibn Zalū, whose school was known as Dār al-Murābiṭūn.

Yaḥyā returned to his people with ʿAbdallāh ibn Yāsīn, who arrived among the Juddāla in 1039/40. Their dual leadership combined Yaḥyā’s tribal authority with Ibn Yāsīn’s religious mission. The Juddāla attacked the Lamṭūna or part of that tribe and compelled them to join the movement.

As Ibn Yāsīn’s reforms and censorship became stricter, Juddāla dissatisfaction grew. The tribe remained acquiescent while Yaḥyā personally supported the reform, but rebelled soon after his death. They then removed Ibn Yāsīn from the administration of their public treasury, expelled him, and looted his possessions.

Later accounts attempted to connect Yaḥyā’s leadership with that of Tāreshnā of the Lamṭūna, proposing succession, marriage ties, and intermarriage between chiefly families. The pages present these reconstructions cautiously and distinguish them from al-Bakrī’s account, which does not specify a relationship between the two chiefs.