Once upon a time, there was a big party for the gods and goddesses on top of a high mountain in Greece. They all gathered and brought a lot of things to show off to each other, including their favorite food and drink.
One goddess, named Eris, felt left out because she wasn't invited to the party. So, she decided to cause trouble by throwing a golden apple with the words "To the fairest" written on it.
Three goddesses, Hera, Athena, and Aphrodite, all claimed to be the fairest and wanted the golden apple. They asked a man named Paris, who was a prince, to judge which of them was the fairest.
Paris decided that Aphrodite was the fairest, and she promised to reward him by giving him the most beautiful woman in the world named Helen. However, Helen was already married, and this caused a big war known as the Trojan War.
So, in short, the Judgement of Paris was a big mess caused by a goddess who wanted to feel included at a party and ended up causing a war because a man picked her as the fairest.