Damocles (fourth century B.C.), a courtier of Dionysius the Elder, tyrant of Syracuse, Sicily. As told by Cicero, Damocles constantly flattered the tyrant and talked so much about the grandeur and happiness of rulers that Dionysius prepared a surprise for him. He invited Damocles to a banquet, gave him the seat of honor, and entertained him royally.
Damocles enjoyed himself until, glancing upward, he saw above his head a sharp sword, held by a single hair. He realized then the constant feeling of danger under which rulers live. “Sword of Damocles” is a figure of speech for a threat of danger that lessens the enjoyment of power and fortune.