Muhammad al-Khwarizmi (c. 780–850) was a mathematician, astronomer and geographer from Khwarezm who worked at the House of Wisdom in Baghdad. His treatise "Kitab al-Jabr" gave its name to an entire branch of mathematics — algebra — while the Latinised form of his own name became the word "algorithm". It was largely through his work that Europe adopted the positional decimal system with Indian numerals that we still use today.