Rainbow: Kamāl al-DīnFārsī and Dietrich de Freiberg

This article examines the views of Greek, Muslim and Latin scientists -from Aristotle to Dietrich de Freiberg and Kamāl al-DīnFārsī- on the rainbow and their explanations in this regard. In Aristotle’s view, the rainbow is produced by the reflection of sunlight on very fine water droplets which make the cloud. In Islamic world, IbnHaytham, who made innovations in old optics, explained the rainbow by “empirical method”. Several centuries later, Kamāl al-DīnFārsī endeavored to interpret IbnHaytham’s works and made a model in order to simulate the rainbow.In Latin world, after translating Islamic scientific heritage in optics, Robert Grossetête and Albert le Grand were the first who study the rainbow; but in fact the Latin world owes the discovery of the rainbow’s reason to Dietrich de Freiberg. He presented his explanation in about 1305 AD/605 AH while Fārsī had also published the results of his studies separately.