Iphigenia at Aulis

In brief
- The fleet bound for Troy lay windbound at Aulis, and the seer Calchas said Artemis was owed a life for an insult: Agamemnon's own daughter.
- Iphigenia was fetched from Mycenae on the pretext of a marriage to Achilles, and taken to the altar instead.
- In the version most often told Artemis swapped a hind for the girl at the last moment; but the fleet had already seen what its commander would trade for a wind.
A thousand ships were drawn up at Aulis with nowhere to go. The wind had turned against them and stayed that way, and an army that cannot sail begins to eat itself. Calchas the seer gave them a reason: Agamemnon had killed a deer in a grove belonging to Artemis and boasted about the shot. The goddess wanted a life back, and had named the one she wanted.
Agamemnon sent to Mycenae for his eldest daughter. The message said that Achilles would not sail without a wedding, and that Iphigenia was to come at once to marry him. Clytemnestra brought her herself, dressed for it. Achilles, who had not been consulted and knew nothing about any of it, learned what his name had been used for when the girl was already in the camp.
What happened at the altar depends on who tells it. Every version has her led out, and her father standing there. In the one most often repeated, Artemis took her at the last instant, set a hind on the altar in her place, and carried her off to Tauris to serve as her priestess. In others the knife simply came down.
The wind changed either way, and the fleet sailed. Clytemnestra went home to Mycenae and waited ten years for her husband to come back from Troy, and when he did she was ready for him.