Archimedes of Syracuse (c. 287–212 BC) was the greatest scientist of antiquity: he founded the sciences of statics and hydrostatics, approximated pi with unprecedented precision, devised the water screw — and, legend says, ran naked through Syracuse shouting 'Eureka!' after discovering the principle of buoyancy.
Mathematician, engineer and inventor, he served the kings of Syracuse and turned his genius to war when Rome besieged his city, holding off the legions for two years before dying — by a Roman soldier's sword — in 212 BC.