Archimedes of Syracuse is generally regarded as the greatest mathematician and scientist of antiquity, and widely considered, along with Newton and Gauss, as one of the greatest mathematicians of all time.

Archimedes' inventions were diverse -- compound pulley systems, war machines used in the defense of Syracuse, and even an early planetarium.

His major writings on mathematics included contributions on plane equilibriums, the sphere, the cylinder, spirals, conoids and spheroids, the parabola, "Archimedes Principle" of buoyancy, and remarkable work on the measurement of a circle.

Archimedes is pictured with the methods he used to find an approximation to the area of a circle and the value of pi. Archimedes was the first to give a scientific method for calculating pi. to arbitrary accuracy. The method used by Archimedes -- the measurement of inscribed and circumscribed polygons approaching a 'limit" (described as 'exhaustion') -- was one of the earliest approaches to "integration".  It preceded by more than a millennia Newton, Leibniz, and modern calculus.

Archimedes was killed in the aftermath of the Battle of Syracuse -- a siege won by the Romans using war machines many of which had been invented by Archimedes himself. Archimedes was killed by a Roman soldier who likely had no idea who Archimedes was.  At the time of his death Archimedes was reputedly sketching a geometry problem in the sand, his last words to the Roman soldier being "don't disturb my circles".