Eris Wasn’t Invited , She Was Mad And Wanted Revenge.
Eris throws an golden apple in the party that says to the fairest of them all and Hera, Athena, and Aphrodite argues about who should receive it
Zeus asked Hermes, the messenger god, to appoint an impartial judge. Hermes chose the beautiful young mortal Paris, who was the son of Priam, the king of Troy.
They all promise him things if he picks them, but Paris chose to pick Aphrodite because his promise was to give Paris prettiest girl in the world, Helen the wife of the Greek king Menelaus.
Paris seduced the queen and abducted her back to Troy. The theft of Helen was an act of outrage which invoked the oath of Tyndareus, requiring the united powers of the Greeks to avenge the wounded honor of Menelaus and retrieve Helen. That started the Trojan War.
Odysseus, had the idea to build a large wooden horse, known as the Trojan Horse. The Greeks hid warriors inside the horse and left it at the gate of Troy, then faked leaving and they opened the gate and the warriors attacked and won the war