about 1050 A.D.
Abū-l-Hasan Alī Ibn Riḍwān. An Egyptian physician who wrote a treatise on Medicine. Daf’ madārr al-abdān bi-ard Miṣr
MS.: Cairo, Dar al-Kutub, MS 18, quoted by Maqrizi (Wiet I, 1, p. 186).
T. : MC 726 r A:1
[p. 241] Burning heat and drought are predominant characteristics of the climate of this place (i.e. Aswan), because the sun heat absorbs all the humidity. For this reason also the local population has a black complexion and kinky hair because of the burning heat of their land. (MC 726 r.).