Damocles

In Greek mythology, Damocles was a courtier in the court of Dionysius the Elder. He mentioned that, as a person of power and authority, Dionysius must be very content and happy. Dionysius invited Damocles to a banquet, which he enjoyed very much sitting at Dionysius' throne. Damocles looked up and saw a sword hanging by a single piece of horsehair directly above his head and he thereafter realized the precarious position rulers are in. The Sword of Damocles is an oft-used allusion to this myth.