For a Maghrebi author as well informed as Ibn al-Ġāzī al-Miknāsī (d. 1504) the Almoravid and Almohad period (11th – 13th cent. CE) is characterized above all by the transformations induced by the massive arrival of black slaves. Indeed, the intensification of relations between the Maghreb and West Africa (Bilād al-Sūdān) led to deep transformations on both sides of the Sahara. Unfortunately, historians since the 19th century have paid very little attention to tranSaharan links. We can see that it is rather the links between al-Andalus and the Maghreb that interested historians. This is regrettable insofar as people originating from Bilad as-Sūdān played an essential role in the Maghreb. We find them, in fact, present both in the messianic movements and in the rise of Sufism in the Maghreb. It is clear, for example, that the founder of the Almohad movement, Ibn Tūmart (d. 1130 CE), was of African descent on his mother’s side. It was the same with almost half of his companions. One sign of the numerical importance of settlement from the Bilād as-Sūdān is the fact that we find those from West Africa present at all levels in the Maghreb, from the entourage close to the Caliph to the rural and Berber world. This is the result of the diplomatic and economic ties forged between the two great powers which governed the Maghreb from Marrakech, and the Bilād as-Sūdān from Awdaġust. It should be noted that if gold and the slave trade motivated these exchanges, the fact remains that both societies, that of Bilād as-Sūdān and the Maghreb, were profoundly and durably transformed by them in ways that the lecture will analyze.