The Furies were ancient Greek avengers usually personified as three ugly, old women carrying torches and covered in snakes. Typically seen as three sisters – Alecto (The Unresting), Tisiphone (The Avenger) and Magaera (The Jealous) – the Furies are the offspring of Gaia and Uranus or, depending on which myth you subscribe to, Nxy (night).¹
In Greece the Furies were also called the Erinyes. The Erinyes mostly punished people within families for their ill deeds on Earth.
The Romans adapted the bulk of Greek myth to suit their own purposes and mindset. The Roman poet Vergil depicts the Furies in the underworld, where they torment the wicked. Although vicious, the Furies mete out just punishments to those who have sworn false oaths.
I see myths like this as primitive or prototypical attempts to understand some basic dynamics of what later would be called the “collective unconscious.”² The old saying what goes around comes around comes to mind. In other words, we can fool others, we can fool ourselves, but sooner or later we have to pay for our bad choices.
² Not to imply that this term is adequate. The Jungian James Hillman rightly points out that the idea of the unconscious is just another concept, another myth. And better understandings of how the mind works in relation to All That Is most likely will come in the future. See James Hillman, The Myth of Analysis.