born September 973, Khwarezm, Khorasan [now in Turkmenistan]
died Dec. 13, 1048, Ghazna, Ghaznavid Afghanistan [now Ghazni, Afg.]

in full Abu ar-Rayhan Muhammad ibn Ahmad al-Biruni Persian scholar and scientist, one of the most learned men of his age and an outstanding intellectual figure.

Possessing a profound and original mind of encyclopaedic scope, al-Biruni was conversant with Turkish, Persian, Sanskrit, Hebrew, and Syriac in addition to the Arabic in which he wrote. He applied his talents in many fields of knowledge, excelling particularly in astronomy, mathematics, chronology, physics, medicine, and history. He corresponded with the great philosopher Ibn Sina (Avicenna). Some time after 1017 he went to India and made a comprehensive study of its culture. Later he settled at Ghazna in Afghanistan. In religion he was a Shi'ite Muslim, but with agnostic tendencies.

Al-Biruni's most famous works are Athar al-baqiyah (Chronology of Ancient Nations); At-Tafhim (“Elements of Astrology”); Al-Qanun al-Mas'udi (“The Mas'udi Canon”), a major work on astronomy, which he dedicated to Sultan Mas'ud of Ghazna; Ta'rikh al-Hind (“A History of India”); and Kitab as-Saydalah, a treatise on drugs used in medicine. In his works on astronomy, he discussed with approval the theory of the Earth's rotation on its axis and made accurate calculations of latitude and longitude. In those on physics, he explained natural springs by the laws of hydrostatics and determined with remarkable accuracy the specific weight of 18 precious stones and metals. In his works on geography, he advanced the daring view that the valley of the Indus had once been a sea basin.