835-912

Arab mathematician who wrote works on ratio, proportion, and arcs. Born in Baghdad and raised in Damascus, Ahmed spent much of his career in Egypt, where he served as private secretary to the powerful ruler Ahmad ibn Tulun. His book on ratio, later translated into Latin by Gerard of Cremona (1114-1187), influenced Leonardo Pisano Fibonacci (c. 1170-c. 1250). Ahmed also wrote a work translated as On Similar Arcs, which developed ideas introduced by Euclid (c. 325-c. 250 B.C.), as well as treatises on the astrolabe and the Centiloquium of Ptolemy (c. 100-170).