Abu Ali al-Hasan ibn al-Haitham (circa 965, probably in Basra; ? 1039 or 1040 in Cairo) was a prominent Arab mathematician, optician, and astronomer. He was originally summoned to Cairo by the court of al-Hakim to regulate the Nile and achieved the position of a vizier there. However, power and career did not entice him as much as science did. Fearing the wrath of al-Hakim, he feigned madness to end his bureaucratic career and dedicate himself to the House of Wisdom established by al-Hakim. After al-Hakim's death in 1021, he seemingly recovered in a miraculous manner.