Sword of Damocles.
As told by the Roman philosopher Cicero in 45 BC, Dionysius II was a tyrant over Syracuse around 400 BC. He had many riches and much power, but had created many enemies in getting there. He was deeply unhappy, worried continuously about the threat of assassination. He lived through this fear in every way.
Damocles served the court, and in one occasion upset the tyrant by expounding on how successful, rich, and happy Dionysius must be. Dionysius offered to allow Damocles to sample his life. He arranged for a throne and servants to shower Damocles with luxuries. As Damocles enjoyed these gifts, he came to notice a sword hanging above his head, suspended only by a strand of horsehair. He was thus unable to continue enjoying his wealth, threatened by death at the slightest change or accident. He begged to be released from the throne.rA5
Evan Andrews, “What Was the Sword of Damocles?,” HISTORY, February 17, 2016, https://www.history.com/news/what-was-the-sword-of-damocles. (See notes.)