Ahmad ibn Fadlan
Important scholars and scientists who flourished in AD 1000 include Abu al-Qasim (Abulcasis), Ibn Yunus (publishes his astronomical treatise "Al-Zij al-Hakimi al-Kabir" in Cairo in c. 1000), Abu Sahl al-Quhi (Kuhi), Abu-Mahmud al-Khujandi, Abu Nasr Mansur, Abu al-Wafa, Ahmad ibn Fadlan, Al-Muqaddasi, Ali Ibn Isa, and al-Karaji (al-Karkhi).