The Libation Bearers, or Choephoroi, is the second play in the Oresteia, a sequence by Aeschylus, which won the dramatic competition at Athens in its original production of 458 BC. Together with its precursor Agamemnon, and the succeeding Eumenides, it forms the only surviving trilogy from Attic tragedy.
The plot centres on the return to Argos of Orestes, the son of the murdered Agamemnon, his recognition by his sister Electra, and his vengeance against his mother, Clytemnestra.
Free online texts
Gutenberg: The House of Atreus; Being the Agamemnon, the Libation bearers, and the Furies, translated by E.D.A. Morshead. Multiple formats.
Internet Archive: The Plays of Aeschylus, translated by Walter Headlam and C.E.S. Headlam. Multiple formats.
Internet Archive: The Choephoroe (Libation Bearers), translated by Gilbert Murray (1923). Multiple formats.
Loebulus. L146 - Aeschylus -- Agamemnon. Libation-Bearers. Eumenides. Fragments. PDF of public domain Loeb edition.
Poetry in Translation: Choephoroi, translated by George Theodoridis (2009). Multiple formats.
University of Adelaide (Internet Archive): The Choephori (Libation-Bearers), translated by E.D.A. Morshead. Multiple formats.
Vancouver Island University: Choephoroi (The Libation Bearers), translated by Ian Johnston. HTML format.
History of Ancient Greece: Early Tragedy and Aeschylus, podcast by Ryan Stitt.
Librivox: The Libation-Bearers (Morshead Translation), public domain audiobook.
Literature and History: Episode 26 - Ancient Greek Theater. Podcast.
Literature and History: Episode 28 - A Mother's Curse - The Oresteian Trilogy, Part 2 - The Libation Bearers. Podcast.
The Great Conversation: Further reading at Tom's Learning Notes
Aristotle: The Poetics.
A.E. Haigh: The Tragic Drama of the Greeks (1896).
Ancient Greek resources: Learn to read Greek classics in the original.