Ibn al-Haytham (Alhazen) Born

Abu Ali al-Hasan ibn al-Haytham, known in the West as Alhazen, was born in Basra around 965 CE. He later worked in Cairo under the Fatimids. He is best known for his research on optics in the Book of Optics. He argued that vision happens when light from objects enters the eye, which contradicted older theories. He also wrote on mathematics and astronomy.