Al-Khwarizmi — The Father of Algebra

Muhammad ibn Musa al-Khwarizmi worked in Baghdad around 820 CE and wrote two books that changed the world. The first gave us the word 'algebra' from al-jabr (reunion of broken parts). The second, on the Hindu-Arabic numeral system, was so influential that al-Khwarizmi's own name, in Latin transliteration, gave us the word 'algorithm.' He systematically solved linear and quadratic equations using prose and geometric arguments — the ancestor of every equation solved in every classroom today.