In the year that the great Chinese philosopher Confucius died in Lu, the Greek philosopher, scientist, and mathematician Leucippus was born in Abdera, a small town on the northern coast of the Greek world.  Although Leucippus' contributions to the field of mathematics were relatively minor, he and his pupil Democritus founded atomic theory, postulating the theory of Atoms and Void.  Leucippus' works The Great World System and On the Mind delineate his theories on the substance of the universe.  Leucippus' Atomism was a precursor to atomic theory as we know it today.

Though Leucippus concentrated primarily on atomic theory, his investigations occasionally ranged into the field of mathematics.  He was one of the first scientists to attempt to square a circle.  He also contributed to the method of exhaustion developed by Archimedes.  Although some historians contended for a time that Leucippus never existed, evidence ascertains both Leucippus' existence and his discoveries.  Leucippus died around 420 B.C.

Author: Tony Brinsko

References:
http://www-history.mcs.st-and.ac.uk:/history/Mathematicians/Leucippus.html

http://www.utm.edu.research/iep/l/leucippu.htm

http://www.perseus.tufts.edu/GreekScience/Students/Marc/short_paper.html

http://w3.mit.edu/wedgwood/www/ancient/atomists.html