When Syracuse was taken, Archimedes was describing mathematical figures upon the earth, and when one of the enemy came upon him, sword in hand, and asked his name, he was so engrossed with the desire of preserving the figures entire, that he answered only by an earnest request to the soldier to keep off, and not break in upon his circle. The soldier, conceiving himself scorned, ran Archimedes through the body, the purple streams gushing from which soon obscured all traces of the problem on which he had been so intent. Thus fell this illustrious man, from the mere neglect to tell his name; for it is due to the Roman general, Marceline, to state, that he had given special orders to his men to respect the life and person of the philosopher.

From Percy Anecdotes