There are many examples of intermittent circulation of dependent populations throughout the Middle Ages between the two shores of the Mediterranean. Despite their shortcomings and silences, the documentary sources sometimes convey a wealth of information, with valuable details that appear only incidentally in the texts. These barely perceptible signs give ample and cumulative expression to a resonant, plural history that breaks with the linearity of the familiar narratives; they can therefore be used to reconstruct the facts and reposition them amid the great variety of dynamics and actors. In the centuries that followed the victory at al-Zallāka, transmigrations accelerated. From the Battle of Alarcos (9 Sha'Bān 591 AH/25 July 1195 CE) to the Battle of Las Navas de Tolosa (Hiṣn al-‘Iqāb) (14 Safar 609 AH/1 July 1212 CE), Ibn Abī Zar' describes processions comprised of Slavs, Andalusians, Kabyles, Arabs and Africans - multiple identities - and the example of thirty thousand black militiamen forming the escort for al-Nāṣir li-Dīn Allāh who, 'armed from head to toe, surrounded the red tent' of the Almohad prince (Ibn Abī Zar', 1860, p. 340).  
These few elements, briefly brought together here, invite us to deconstruct the obsessive theory of an age-old confrontation between two implacably opposing blocs; a vision based on the binary paradigms of blacks and whites, slaves and free, East and West, Islam and Christianity. As we have seen, the documentary sources can be used to widen the scope of the study and reassess the place of the actors. They provide significant data that put the centrality of the Arabs into perspective and pave the way for a historiographical investigation that could shed new light on the dynamics and plurality of this long history of Euro-African interaction.