Like many of their later Renaissance counterparts, most Muslim scientists and thinkers were multidisciplinary, and produced remarkable works of in many fields. A few of the more famous scholars include: Ibn Hayyan (Geber, 738-813) - known as the father of chemistry. Al-Khawarizmi (Algorizm, 750-850) - invented algebra and was instrumental in the development of trigonometry, calculus, and the use of algorithms. Ibn Firnas (died 888) - developed the mechanics of flight before DaVinci; he also built a planetarium. Al-Razi (Rhazes, 864-930) - a great physician who identified and treated smallpox. Al-Zahravi (Albucasis, 936-1013) - recognized as the father of modern surgery. Ibn Sina (Avicenna, 981-1037) - a very well known physician, authored the "Cannon of Medicine" and the "Book of Healing." His writings were considered the authority of medicine for over five hundred years. Al-Idrisi (Dreses, 1099-1166) - made the first world maps that clearly showed North, Central, and South America. Ibn Rushd (Averroes, 1128-1198) - a great philosopher, astronomer, and physician. Ibn Batuta (1304-1378) - an avid world traveler, writer and geographer; he visited most of then-known world from Spain, to parts of Africa, to China.