Rhazes (al-Razi, c. 865-925) studied the natural sciences, alchemy, and music in his youth. At the age of 30, he travelled from his home in north Persia to Baghdad to study medicine. A polymath, he wrote about 200 books on medicine, logic, philosophy, theology, the natural sciences, alchemy, astronomy, and mathematics. Like Galen, he was careful to make unpleasant tasting drugs palatable when prescribing for the nobility, but was sceptical of secret remedies for which ‘wicked people' made unsubstantiated claims. Rhazes claimed not to ‘accept any property as authentic unless it has been examined and tried'.

Oil painting by Ernest Board (1877-1924).