Iphianassa (daughter of Agamemnon)

In the Iliad, Iphianassa (Ἰφιάνασσα) is an obscure and controversial daughter of Agamemnon and Clytaemnestra, sister to Laodice and Chrysothemis, sometimes considered identical to Iphigeneia.

Mythology
Extant plays by Sophocles, Aeschylus and Euripides on the tale of Orestes and Electra do not include her as a character. This is consistent with the theory that she and Iphigeneia are one and the same. On the other hand, Sophocles does mention her, and hints that she lives in the palace of Aegisthus and Clytemnestra, together with Electra and Chrysothemis.

Lucretius, in De Rerum Natura, mentions Iphianassa being sacrificed by her father on the altar of the "Virgin of the Crossways" (Triviai virginis) Diana at Aulis as an offering to ensure a successful voyage, in undoubted reference to the tradition of Iphigeneia. Lucretius cited this episode to make the point: "Superstition (religio) was able to induce so great an evil."