In Greek mythology, Ismene ( ; Ancient Greek: Ἰσμήνη, romanized: Ismḗnē) was a Theban princess. She was the daughter and half-sister of Oedipus, king of Thebes, daughter and granddaughter of Jocasta, and sister of Antigone, Eteocles, and Polynices. She appears in several tragic plays of Sophocles, including Oedipus Rex, Oedipus at Colonus, and Antigone. She also appears at the end of Aeschylus' Seven Against Thebes.
Family
Traditionally, Ismene was the daughter of Oedipus and Jocasta (or Epicaste), king and queen of Thebes. She had three full siblings: Antigone, Polynices, and Eteocles, and her father Oedipus was also her half-brother, being Jocasta's son.
In the lost Oedipodea, the archaic epic poem that narrated the adventures of Oedipus and inspired later authors, the children of Oedipus were mothered by Euryganeia, daughter of Hyperphas. In the Odyssey, Homer writes that, after Oedipus' incestuous marriage to his mother, the gods revealed the incest "straightaway." In reference to this, Pausanias claims that the notion that the gods revealed it straightaway is incompatible with the idea that Oedipus and Jocasta had four children, so his children must have been born to another woman.
That being said, there is no absolute confirmation that Ismene was a part of the Oedipodea at all, let alone as Oedipus' daughter. Ismene was likely a separate Theban heroine integrated into Oedipus' myth and family tree by the tragedians during the fifth century BC.
Mythology
The seventh-century BC poet Mimnermus wrote that Ismene was murdered by Tydeus, one of the Seven who took arms against Thebes. In this account, Ismene was dallying with her lover Theoclymenus when Tydeus surprised them, having been told of their whereabouts by the goddess Athena. Tydeus then slew Ismene. It is not clear what Athena's motivation was; perhaps here Ismene was a priestess of Athena, so the goddess was punishing her dalliance. This tradition cannot be reconciled with the events...
