965 - Alhazen was born in Basra, Iraq as Abu Ali Hasan Ibn al-Haitham.
1015-1021 - He wrote his seven volume treatise on optics Kitab al-Manazir which drastically transformed the ancient Greek understanding of vision. Discovered the the laws of refraction, carried out the first experiments on the dispersion of light into its constituent colours. He made the important observation that the ratio between the angle of incidence and refraction, investigated the magnifying power of a lens, discussed the density of the atmosphere and related it to altitude. Discovered that the twilight only ceases or begins when the Sun is 19° below the horizon, developed analytical geometry by establishing linkage between algebra and geometry.
1040 - He died in Cairo, Egypt.
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