al-Razi (physician)

Abu Bakr Muhammad ibn Zakariyya al-Razi (c. 854-925 CE / 240-313H), known in Europe as Rhazes, was the greatest physician of the medieval world. Born in Ray (near modern Tehran), he headed hospitals in Ray and Baghdad. His encyclopedic al-Hawi (Continens) — 23 volumes summarizing Greek, Syriac, and his own medical knowledge — was used as a textbook in European universities until the 17th century. He made the first clear clinical description distinguishing smallpox from measles. He was also a pioneer of experimental medicine, testing medications on animals before humans. Note: his philosophical writings (particularly on religion and prophecy) are considered heretical by Islamic scholars and are not endorsed here.