Cassandra, the daughter of king Priam of Troy, was cursed to speak true prophesies that no one believed. However, there is not a trace of this story in the Homeric epics, where she doesn’t seem to possess any prophetic powers.
There are a few early references to Cassandra’s prophetic powers, mostly dating to the later sixth century BC (e.g. Pindar’s Pythian 11.33). For the earliest version of the tale as we know it today we have to turn to Aeschylus’ play Agamemnon, which dates to a little before the middle of the fifth century BC. In the play, we learn that Cassandra had originally promised herself to the god Apollo, who gave her the gift of foresight as a reward. But when she reneged on her promise, she angered Apollo, and presumably as a result she was cursed to never have anyone believe her prophesies.
In the Bibliotheca of Pseudo-Apollodorus (first or second century AD), Cassandra alongside the priest Laocoon warn the Trojans about the Wooden Horse being filled with Greek warriors ready to take Troy by surprise. But Laocoon is devoured by a serpent sent by the gods and no one believes Cassandra anyway, so that the Trojans disregard their warnings and bring the timber construction inside the city (E.15.17).
When night falls, the Greeks exit the Wooden Horse and open the gates for the rest of the army. Troy is conquered and sacked. Cassandra flees to the temple of Athena and wraps her arms around the statue of the goddess. The Lesser Ajax pulls her away from the statue, as in this articles featured image, which is a detail from a fresco at Pompeii. He rapes her on the temple floor; an event that may have already been familiar to the poet Alcaeus (ca. 600 BC), but the evidence is fragmentary. According to ancient commentators, as well as later writers like Quintus, this caused the statue to turn its eyes upward to the roof in anger. Indeed, rage at the desecration of Athena’s temple – and not any sympathy toward poor Cassandra – is the ultimate cause of the Greeks’ later troubles at sea.
The Greeks failed to punish Ajax for his crime, but he was ultimately drowned by the gods. Cassandra was taken as a concubine by Agamemnon to Mycenae, where she died along with her captor as part of the evil plot hatched by Agamemnon’s wife Clytemnestra and her lover, Aegisthus. What makes her ultimate fate even more poignant is that she would have known exactly when and how she was to be killed, but could have done nothing to prevent it.