The Trojan War lay on the horizon for the Greek fleet, but Agamemnon, supreme commander of all Hellenic forces, made the fatal mistake of killing one of Artemis' sacred animals, some say a deer, others a hare and its children. She responded by unleashing battering winds upon the ships so that they could not sail.
Agamemnon was told that he needed to sacrifice his oldest daughter (Iphigenia) to Artemis, otherwise the fleet would never reach Troy. As a war that would be the defining event of his life and career, Agamemnon decided to concede to the demand.
Luring his daughter to the altar with the false promise of marriage to Achilles, he prepared to make the ultimate sacrifice, but before he could deliver the fatal blow, Artemis Herself came and spared Iphigenia, putting a deer upon the altar in her place, and later taking the girl to serve as Her priestess to the City of Tauris.