Les lettres du pouvoir au Sahel islamique Marques, adaptations et continuités administratives au Borno (1823-1918)

The Power Letters in Islamic Sahel. Marks, Adaptations and Administrative Continuities in Borno (1823-1918). - Through the analysis of thirty-seven diplomatic letters from Borno (North-Eastern Nigeria), dated from 1824 to 1918, this article sheds new light on the functioning of an administration serving a Muslim dynasty in the Sahel before colonization. Beyond the norms that characterize the writing of power in Borno, the graphic variations of letters reveal an administration at work, one that adapts its scriptural practices according to the recipient. The graphological analysis of the handwriting then makes it possible to identify a family of secretaries dating back to the 16^th century, whose charge was independent of the palace revolutions. Descendants of the imam Ahmad _. b. Fur_.tū (c. 1576), these secretaries ensured an extraordinary continuity of power writing practices in Borno until the early years of colonization.