In Greek mythology, Cassandra ("she who entangles men") (also known as Alexandra) was a daughter of King Priam of Troy and his queen Hecuba, who captured the eye of Apollo and was granted the ability to see the future.
In an alternate version, she spent a night at Apollo's temple with her twin brother, at which time the temple snakes licked her ears clean so that she was able to see the future. This is a recurring theme in Greek mythology, though sometimes it brings an ability to understand the language of animals rather than an ability to know the future.
However, when she did not return his love, he placed a curse on her so that no one would ever believe her predictions. From the play Agamemnon, it appears that she made a promise to Apollo to become his consort, but broke it, thus incurring his wrath. When Cassandra foresees the destruction of Troy (she warns the Trojans about the Trojan Horse, the death of Agamemnon, and her own demise), she is unable to do anything about them. Her family believes she is mad, and, according to some versions, kept her locked up because of this. From her appearences in various plays, it seems that the incarceration drove her truly mad, at least by the fall of Troy. Coroebus and Othronus came to the aid of Troy out of love for Cassandra. Cassandra was also the first to see the body of her brother Hector being brought back to the city.
After the Trojan War, she was raped by Ajax in the temple of Athena after seeking shelter there. Cassandra is then taken as a concubine and sex slave by King Agamemnon of Mycenae. Unbeknownst to Agamemnon, while he was away at war, his wife, Clytemnestra, had begun an affair with Aegisthus. Upon Agamemnon and Cassandra's arrival in Mycenae, Clytemnestra asks her husband to walk across a purple carpet. He initially refuses, but gives in and enters, ignoring Cassandra's warnings. Clytemnestra and Aegisthus then murder Agamemnon and Cassandra. Some sources mention that Cassandra and Agamemnon have twin boys Teledamus and Pelops, who are killed by Aegisthus.