Answer:
The prophecy of the Oracle that the Trojan War will begin with an apple is rightly so because the fight for the apple led to Aphrodite's claim for it. This then led to her promise to help get Helen for Paris, which led to the Trojan War. And the war ended after the Greek armies sneaked into the Trojan city by hiding inside a wooden horse sent to the Trojans as a peace symbol.
Explanation:
The Oracle's prophecy of<em> "What Began with an Apple; Must End With a Horse"</em> reveals what the Trojan War will be like and why it must be so. The case of <em>“the Apple</em>” is the apple of discord that the three goddesses fought over. This is the Judgement of Paris, where the three goddesses Aphrodite, Athene, and Hera went to Paris, the shepherd to lay claim to the apple which will claim her the fairest.
Paris chose Aphrodite as the rightful owner of the golden apple for she had promised him to get Helen, the most beautiful girl for him. And it was this promise which led to the abduction of Helen from her husband Menelaus, the King of Sparta. This further led to the Battle of Troy which ended only after the Greeks sneaked into the Trojan city inside a wooden horse.
Thus, the prophecy had rightly foretold the beginning and end of the Trojan war, which will begin with the Apple of Discord and end with the wooden horse filled with the Greek armies sneaking inside Troy.