Ibn al-Haytham

Al-Haytham, also known as Alhazen, was an Islamic mathematician who wrote early works on optics as well as geometry and number theory. He was born, possibly in Basra in Persia (now Iraq), in 965 and died, possibly in Cairo, Egypt, in 1040. Around the year 1000 he discovered Wilson's theorem, which says that a number n is prime exactly when the factorial of n minus one is one less than a multiple of n, and he is an early number theorist and the author of a celebrated work on optics.