The great wealth made the Abbasids able to support learning and arts. Muslims believed long before Columbus's time that the earth was round. They invented algebra. They wrote the first accurate descriptions of measles and smallpox. They had clean hospitals. They built the Bayt-al-Hikmah (House of Wisdom) in which scholars from different lands came and studied. It served as a museum, library, translation office, school, and meeting center. Books about mathematics, meteorology, optics, mechanics, astronomy, philosophy, medicine, etc. were translated into Arabic from Hebrew, Greek, Persian, Syriac, and other languages. Al-Razi, Ibn Sina, Al-Biruni, and Al-Khwarizmi were some of the famous scholars of that time. Muslims collected writings of the schools of Alexandria and the best philosophical works of ancient Greek. There were special departments under qualified professors for promotion and prosecution of special branches of study. Astronomical observations were made in Mamun's reign. Among these equinoxes, eclipses, the apparitions of comets and other celestial bodies was most important. The size of the earth was calculated from the measurement of a degree on the shores of the Red Sea. At this time, Europe was asserting the flatness of the earth. Abul Hassan invented the telescope. The telescope was improved and used in the observatories of Maragha and Cairo with great success. The first observatory of Islam was made in Mamun's reign at Shamassia on the plains of Tadmur. Afterwards several more were created.

Stephen George