Once Cassandra had been cursed by Apollo to prophesy the truth but never be believed, Troy was doomed. Countless times before and during the Trojan War Cassandra predicted what would come of the war, but no one believed her. Always it was Cassandra who recognized a face, who predicted a fateful occurrence, who ran around the ramparts of the city with her hair flying around her shoulders, crying and spouting oracles that no one understood. Most people considered her insane and tried to subdue her, but she was only trying desperately to warn her people of impending disaster.
The Recognition of Paris
The first mention of Cassandra as a prophetess is in the story of the recognition of Paris. When Paris was born, there was an oracle that the child born would be the destroyer of the city. In Euripides' Andromache, Cassandra "shouted her order to kill him, the city of Priams' great ruin!" (295) So sorrowful Hecabe and Priam had Paris taken from the city and abandoned in the wilderness. But instead of dying, Paris was suckled by a she-wolf and eventually adopted by shepherds. While he was a young shepherd he was used by the gods in the famous judgment of the goddesses, in which he chose Aphrodite who promised him he could have Helen. Soon after, Paris returned to his home city during funeral games and conquered even heroic Hector in the contests. A fight ensued over the prize of a bullock and Paris fled to the Altar of Zeus where Cassandra recognised him as her brother. He was immediately accepted as the son of King Priam and the curse upon him was forgotten. (Pseudo-Apollodorus p2.47) There is no reference as to whether or not Cassandra predicted his doom at this time.
Priam and Hesione
One of the apparent causes of the Trojan War was the abduction of Priam's sister, Hesione. She had been taken to Greece by Telamon the Aeacid, and Priam sent Antenor and Anchises to Greece to demand her return, but they were rejected and driven away. By this time Cassandra was already predicting the tragic end of the Trojan War, but of course no one believed her. Priam was upset by her raving and had her locked up in a pyramidal building on the citadel to avoid anymore scandal. He ordered the wardress who cared for her to keep him informed of all her "prophetic utterances". (as related in Graves p626)
Cassandra Warns Paris
When Paris and Aeneas set off for Sparta to kidnap Helen, Paris' promised prize, Cassandra, "her hair streaming loose", predicted the doom his voyage would cause, and her prophetic twin Helenus agreed. They were ignored, though, and Priam refused to pay any attention to either of his prophetic children in this matter. (as related in Graves p635)
Cassandra's Mourning for Hector
In the Iliad, Priam went to the Greek camp to request the body of Hector, which the enraged Achilles had been desecrating and mutilating. Priam begged for an eleven day truce in order to complete mourning for Hector, and Achilles agreed. Priam departed with Hector's body and returned to Troy late at night. No one saw him coming except for Cassandra, "golden as goddess Aphrodite", who had climbed the ramparts and saw the chariot and wagon from a distance. She began to scream so loudly that the city walls echoed and the Trojans were roused from their beds. She lamented: "Come, look down, you men of Troy, you Trojan women!/ Behold Hector now--if you ever once rejoiced/ to see him striding home, home alive from battle!/ He was the greatest joy of Troy and all our people!"(Iliad 24.819-32, Fagles translation))
The Trojan Horse
One of Cassandra's most famous predictions was that of the Greek siege behind the gift of the Trojan Horse. Related in Vergil's Aeneid ii, the Trojans exultantly accepted the Greek gift of a giant wooden horse. Only Cassandra remained quiet and subdued. "Four times [the horse] struck [the gates]: as oft the clashing sound/ Of arms was heard, and inward groans rebound./ Yet, mad with zeal, and blinded with our fate,/ We haul along the horse in solemn state;/ Then place the dire portent within the tow'r./ Cassandra cried, and curs'd th' unhappy hour;/ Foretold our fate; but, by the god's decree,/ All heard, and none believ'd the prophecy." (Aeneid 2.323, Dryden translation) Late that night the Greeks left the horse and began the final attack on Troy.
Cassandra's Revenge
In Euripides' Trojan Women354-65, Cassandra comforts her stricken mother during the fall of Troy by predicting the doom of the Greek's return home:
O mother! Crown my head with victor's wreaths; rejoice in my royal match; lead me and if you find me unwilling at all, thrust me there by force; for if Loxias is indeed
a prophet, Agamemnon, that famous king of the Achaeans will find in me a bride more vexatious than Helen.
For I will slay him and lay waste his home to avenge my father's and my brothers' death. But let that go; I will not tell of that axe which shall sever my neck and the necks of others, or of the conflict ending in a mother's death, which my marriage shall cause, nor of the overthrow of Atreus' house. But I, for all my frenzy, will so far rise above my frantic fit, that I will prove this city happier far than those Achaeans, who for the sake of one woman and one passion have lost a countless army in hunting Helen.