Abū ʿAbdallāh Muḥammad ibn Mūsā al-Khwārizmī, earlier transliterated as Algoritmi or Algaurizin, (780 – 850) was a Persian mathematician, astronomer and geographer during the Abbasid Empire, a scholar in the House of Wisdom in Baghdad.

In the twelfth century, Latin translations of his work on the Indian numerals introduced the decimal positional number system to the Western world. His Compendious Book on Calculation by Completion and Balancing presented the first systematic solution of linear and quadratic equations in Arabic.

Some words reflect the importance of al-Khwarizmi’s contributions to mathematics. Algorism and algorithm stem from Algoritmi, the Latin form of his name. His name is also the origin of (Spanish) guarismo and of (Portuguese) algarismo, both meaning digit.

Al-Khwārizmī’s third major work is his Kitāb ṣūrat al-Arḍ, “Book on the appearance of the Earth” or “The image of the Earth”, which was finished in 833. It is a revised and completed version of Ptolemy’s Geography, consisting of a list of 2402 coordinates of cities and other geographical features. It details the British Isles and mentions British landmarks.

http://en.wikipedia.org/wiki/Mu%E1%B8%A5ammad_ibn_M%C5%ABs%C4%81_al-Khw%C4%81rizm%C4%AB