" The Father of Algebra." (780 - 845 C.E.) Abu Abdullah Muhammad bin Musa Al-Khwarizmi was a Persian mathematician and astronomer. He wrote the famous book "Al-Kitab Al-Mukhtasar fi Hisab Al-Jabr Wa'l-Muqabala" ("The Compendious Book on Calculation by Completion and Balancing") in 830. The book offered a systematic and logical approach to solving linear and quadratic equations. This became the premise of algebra. He is also responsible for introducing the Hindu-Arabic numerals to the West, thus becoming the golden standard in global mathematics. He also refined Ptolemy's theories on geography to design the first map of the then "known world", wrote on spacial, time-mechanical devices such as the clock, astrolabe, and sundial, made a table of trigonometric functions, and geometrically interpreted the conic sections.
Sure. Newton created the calculus. Liebniz refined it. Kepler popularized it. Lambert generalized it. And Euler organized it. If it wasn't for Al-Khwarizmi, however, most people wouldn't even understand basic arithmetic.