Scholars of the House of Wisdom: Al-Khwarizmi, Al-Biruni, and Ibn Sina

Al-Khwarizmi and the Invention of Algebra

Muhammad ibn Musa al-Khwarizmi (c. 780–850 CE) was a Persian mathematician and astronomer working in Baghdad's House of Wisdom. In his seminal 820 CE text Al-Kitab al-Mukhtasar fi Hisab al-Jabr wa'l-Muqabala ("The Compendious Book on Calculation by Completion and Balancing"), he introduced systematic algebraic methods for solving linear and quadratic equations.

Al-Khwarizmi also popularized the Hindu positional decimal numeral system (including zero) throughout the Islamic world. When his treatises were translated into Latin in 12th-century Europe, his Latinized name gave birth to the word algorithm, while al-jabr became algebra.

Al-Biruni: Measuring Earth's Radius

Abu Rayhan al-Biruni (973–1048 CE) was an extraordinary astronomer, physicist, geographer, and ethnographer. Working in Central and South Asia, Al-Biruni devised an ingenious trigonometric method to measure the circumference and radius of the Earth using mountain height and horizon dip angles.

Calculated at a fortress near Nandana in modern Pakistan, Al-Biruni's value for the Earth's radius (6,339.6 km) was within 1% of modern satellite measurements—an achievement unmatched for six centuries.

Ibn Sina and the Canon of Medicine

Ibn Sina (known to the West as Avicenna, 980–1037 CE) authored Al-Qanun fi al-Tibb ("The Canon of Medicine"), a 14-volume medical encyclopedia that systematized ancient Greco-Roman medical theory with empirical Islamic clinical observations. Translated into Latin, the Canon remained the principal medical textbook in European universities until the mid-17th century.