Around 820, working at the Abbasid caliph al-Ma'mun's House of Wisdom in Baghdad, the scholar Muhammad ibn Musa al-Khwarizmi wrote Kitab al-jabr wa'l-muqabala, which set out systematic procedures for solving linear and quadratic equations and gave algebra both its method and its name (al-jabr). In a separate work he explained the Hindu–Arabic decimal place-value numerals, which spread through his writings into the wider Islamic world and eventually Europe. The Latin form of his name, Algoritmi, became the word 'algorithm'. His texts were standard reference works for centuries.
Al-Khwarizmi's algebra and decimal arithmetic supplied the calculating tools later used to survey land, divide estates and inheritances, levy taxes and compute the dimensions of buildings, fortifications and city layouts.