Now before we can get to the main portion of our story, we need to discuss the birth of a child named Paris in the city of Troy. Just before his birth, his mother dreamed that she gave birth to a flaming torch. This dream was interpreted by the seer Aesacus as a foretelling of the downfall of Troy, and he declared that the child would be the ruin of his homeland. On the day of Paris' birth it was further announced by Aesacus that the child born of a royal Trojan that day would have to be killed to spare the kingdom, being that the child's birth would implement the prophecy. (Wow, this kid is facing the wrath of the world before he was even born!)
Though Paris was indeed born before nightfall, he was spared by Priam, his father, who was unable to kill his son. His mother, Hecuba, also was unable to kill her child, despite the urging of a priestess of Apollo. Instead, Paris' father prevailed upon his chief shepard, Agelaus, to remove the child and kill him. (I love him to much therefore you must kill him . . . )
But even this effort would not be successful, because the herdsman, unable to use a weapon against the infant, left him exposed on the slopes of Mount Ida. His plan was to return in a few days, to recover the child's body. Yet to his great astonishment, after returning nine days later, he found the child still alive, and taking that as a sign from the gods, brought him home in a backpack to rear as his own. He returned to Priam bearing a dog's tongue as evidence of the deed's completion and no one was ever the wiser.
Fast forward and Paris has discovered his royal heritage, and despite his childhood challenges and that pesky prophecy, claimed his title as Prince of Troy. He is also known far and wide for his understanding of female beauty and for his fair judgements. (Boy, talk about an impressive skill set . . . )
Okay, so now we're ready to rejoin our story of Eris's revenge.
All the Olympian gods were invited to the wedding of Peleus and Thetis except Eris, who was the goddess of discord. (Hence, why she probably wasn't invited) Angry, Eris decided to teach the assembled Olympians a lesson. She crashed the wedding and threw among the gods a golden apple on which was engraved the words, ‘For the most beautiful.’
Three goddesses – Hera, goddess of household, Athena, goddess of skills, and Aphrodite, goddess of beauty – claimed the apple and fought over it. No god, not even Zeus, (Ha!) dared judge who of the three goddesses was the most beautiful, and worthy of the apple.
Finally, Zeus punted on his responsibility and instructed the goddesses to visit Paris, the young prince of Troy, and that he would pick a winner among the three. (And you thought your job was thankless) The three goddesses presented themselves to Paris and tried to impress him with their beauty. When he could not decide, each then tried to bribe him secretly. Hera promised to make him ruler of the greatest kingdom in the world. Athena promised to make him the most admired warrior in the world. Aphrodite promised him the hand of Helen, the most beautiful woman in the world.
Paris, however, thought that Athena and Hera's gifts to him were of little value because he knew that his father and the city of Troy were at peace and that there was no prospect of war. So instead of picking Athena and Hera as the fairest of all, Paris picked Aphrodite because he thought her gift was the best. This made Hera and Athena deeply angry that Paris had not picked them and they disappeared to Olympus, forcing the rest of the gods to pick a side in the war that was to come.
Thus, the cause of the Trojan War was not so much human folly as it was the pettiness of the gods.
Aphrodite had neglected one very important detail, Helen was already married to King Menelaus of Sparta. Paris, not aware that his betrothed belonged to another, prepared to sail to Greece to win his prize. Upon arriving in Sparta, he was welcomed by King Menelaus, who offered him hospitality. Soon afterwards, Menelaus sailed to Crete to attend the funeral of Katreus, the king of the island (who was also Menelaus' maternal grandfather), leaving Helen to the care of his guests. Paris took advantage of his absence to court Helen, and as soon as she was willing, he eloped with her, (or kidnapped her depending on whose viewpoint you believe) and the two set sail for Troy.
Upon Paris and Helen's arrival at Troy they are met by the king and queen were overjoyed to see their son and let them stay, in spite of their daughter, Paris's older sister, Cassandra's warnings. Cassandra had the gift of seeing into the future, given by Apollo himself. In exchange for the gift, she had to give him her love and hand in marriage, however, after she received the gift, she broke her promise. Almost every woman Apollo loved, for example, Daphne, and Koronis, all had unfortunate endings. Cassandra didn't want to end up like them. Apollo was infuriated and changed Cassandra's gift into a curse. She would utter true prophecies, but nobody would believe her.
Finding his wife had vanished, Menelaus recruited his powerful friends to bring her back to his kingdom. These men represented the power, wealth, and military prowess of Achaea. Thus, the whole might of Greece waged war with Troy, which included their generation's greatest heroes.
In Homer's Iliad, it is said that the Trojan War took ten years of fighting between the Greek armies and the Trojan army. Nine of the ten years were spent fighting between the armies but the Greeks didn't have an advantage since Achilles, a son of Thetis, chose to spend his time in his tent, not participating in the war between the Greeks and the Trojans. However, in year ten, Achilles joins the battle when he heard that Paris' oldest brother, Hector, had killed his best friend, Patroclus, while Patroclus was wearing Achilles' armor.
Achilles then killed Hector in a duel that took place around the walls surrounding Troy. After killing Hector, Achilles proceeded to tie Hector's mangled body to his chariot as he drove around the city walls for twelve days, displaying Hector's corpse for all to see.
This killing enrages Paris, who later slays Achilles as the latter is storming the walls of Troy - he shoots an arrow, guided by Apollo, into the hero's heel, killing him. Shortly afterward, Paris is later slain by Philoktetes, using the poisoned-tipped arrows of Hercules.
After the deaths of so many heroes, the Greeks came up with the ruse of the Trojan Horse, planned by Odysseus. The Greeks hid their best warriors inside a wooden horse that they had built, while the remaining fleet sailed off into the distance, just out of sight of the Trojans. The Greeks left a note saying that they admitted defeat and were offering the horse to them as a gift. Laocoön, the priest of Poseidon, tried to warn the Trojans that it was a trap, uttering the famous line: "Beware of Greeks bearing gifts".
The Trojans chose to ignore this wisdom and brought the horse into the city. The horse was too large to fit through the city gates, so, the Trojans had to tear down a large section of the city walls. The Trojans rejoiced, and held a party to celebrate. In the middle of the party, princess Cassandra burst through the doors, holding a torch and axe. "This is a trap!" she shouted, and tried to burn the wooden horse with the torch. The guards restrained her, pleading with her to not do anything rash. Cassandra then tried to destroy the horse with her axe, and was again restrained. She finally gave up, resolved to accept her fate and painfully aware that her curse would last her lifetime.
When night fell, the Achaeans inside the horse came out and opened the city gates, letting the rest of the army inside, which wasn't hard, since the Trojans had already destroyed part of the city walls for the Trojan Horse (The Achaeans built the horse too large for the city gates on purpose, it was part of the plan).The Achaeans burned Troy to the ground, slaughtering all of the men, with the women and children being sold into slavery; and a number of the Greeks even desecrated the gods' temples, angering them.
The few Trojans that managed to escape met with Aeneas, son of Aphrodite and the Trojan prince Anchises, far away from the beaches. Aeneas and the other survivors sailed away and eventually, after many trials and long suffering, they founded a new city in Italy, called Rome.