The Fatal Constancy

The Fatal Constancy is a 1723 tragedy by the British writer Hildebrand Jacob. The original cast included Barton Booth as Omphales, John Mills as Zimon, Colley Cibber as Tryphon, Charles Williams as Ammon and Mary Porter as Hesione.

Plot
In ancient Greece, a man, Ammon, is upset that his adopted sister, Hesione, whom he is in love with, is going to marry a soldier, Omphales. Ammon decides to blackmail a priest, Zimon, who is officiating the wedding of Omphales and Hesione, into delivering a bad omen that will prevent the two from marrying one another. Tryphon, Hesione's father, believes Zimon's falsehood, and refuses to let his daughter wed Omphales. Omphales leaves the city and conjures up an army of soldiers to overtake Tryphon, but is, along with his allies, defeated and killed. As a result, Hesione, who has been in a state of madness since Omphales's departure, dies. Ammon feels guilty and bemoans his actions.

Influences
The prologue to the play states that The Fatal Constancy resembles Ancient Greek drama in its structure; the play takes place over a 24 hour period, and all the deaths take place offstage.