We learn at school that Isaac Newton is the father of modern optics, that Copernicus heralded the birth of astronomy, and that it is Snell's law of refraction. But what is the debt these men owe to the physicists and astronomers of the medieval Islamic Empire?

Men such as ibn al-Haytham, the greatest physicist in the two thousand year span between Archimedes and Newton, and whose Book of Optics was just as influential as Newton's seven centuries later; or Avicenna and Biruni the Persian polymaths who argued over such topics as why ice floats and whether parallel universes exist; or Ibn Sahl who came up with the correct law of refraction many centuries before Snell; or the astronomers al-Tusi and ibn al-Shatir, without whom Copernicus would not have been able to formulate his heliocentric model of the solar system.

In this lecture I will describe these characters and their forgotten contribution to physics and astronomy.