has come to replace the noun 'abd (slave). This lexical retroversion had the effect of reinforcing the similarity between stereotypes that mixed up social, ethnic and anthropological traits. It ultimately resulted in an essentializing category: ${ }^{1}$ a persistent prejudice that still haunts Arab societies. The author also puts the spotlight on another ethnic referent, that of Zanj, (plural Zunüj, and Zanjiyyāt in the feminine), often used in narrative texts to describe the enslaved black people. Originally this word was attributed to East African Bantu communities. Over time the word became widespread. 'Abd, 'aswad and Zanj became interchangeable terms. As nouns, they stood for a confusion of biological, social and cultural identities. The Risāla fī fakbr al-Sudān highlights the resonance of these discursive amalgams and their impact on collective mentalities.  
It is clear that these realities date back further than al-Djāhiz's era. The main argument of this epistle is one of transparency and a strong need for a debate on the representation of blacks over the two periods of history: pre- and postIslam. He writes to the blacks, for the attention of Arabs:  
This is one aspect of your misguidance. In pre-Islamic times you considered us equals and were happy for us to marry your daughters and wives. But once the laws of Islam were established you decreed that that was all obsolete (al-Djāhiz, op. cit., vol. I, p. 197)  
A little further on he adds:
God - Almighty - did not create us black to disfigure us. Rather it is the climate in our countries that has caused that situation (ibid., p. 219).  
Turning to the register of resistance, the author recalls certain episodes of their history in the lands of Islam. He recollects the mutiny that happened in the second half of the eighth century before the great rebellion of 869 CE: