Originally, “The Eumenides” were nothing but a personification of curses pronounced upon a guilty person. The name Erinys, which is the more ancient title, was derived by the Greeks, while the name Eumenides signifies “well-meaning” and was used in reference to gods because people were too scared to use their real names in conversation.

At the start of “Eumenides,” a priestess declared that Apollo would be a prophet. The priestess was frightened of the powerful furies and fear overwhelmed her. Vowing to protect Orestes, Apollo called on Hermes to watch over Orestes, so Hermes got Orestes out of Athens. The furies were angered by this, and tried to take Orestes to the underworld to face judgment.  

The furies invoked justice and demanded expiation. Fate gave the furies this work, since immortal gods could not lay hands on the furies, who are the ultimate justice. Moreover, the furies could not be appeased, even after the Greeks gave Athena land in Troy and Orestes sacrificed pigs. Therefore, Apollo bore responsibility and Athena could not dissolve the dispute. The furies consented to a trial, but then quarreled with the god Apollo over whose system of justice would decide it. 

Since the gods went against the furies, the furies vowed twice to destroy the city of Athens. However, they slowly consented to the gods and eventually promised positive sanctions to the Greeks. This resolved the conflict between the gods of Mount Olympus and the gods of the underworld, and Athens agreed to sacrifice to both sets of gods in exchange for protection. 

In the “Oresteia Trilogy,” which are the books of “Agamemnon,” “The Libation Bearers,” and “The Eumenides,” the furies had power over the gods, but the gods could still defy them due to their great strength. In the end, the furies, the gods of the underworld, and the gods of Mount Olympus came to a civic resolution, and the Greek people agreed to worship all of them.