The Collaborative International Dictionary of English v.0.48:

Demosthenes \Demosthenes\ prop. n.
   a famous Grecian orator, born circa 385 BC, died circa 322
   BC.
   [WordNet 1.5]

WordNet (r) 3.0 (2006):

Demosthenes
    n 1: Athenian statesman and orator (circa 385-322 BC)