In Greek mythology, Iphigenia was a daughter of King Agamemnon and Queen Clytemnestra, a princess of Mycenae. When Agamemnon offended Artemis and the Greek fleet was becalmed at Aulis, the seer Calchas declared that only the sacrifice of Iphigenia would free the ships for Troy. In some versions she dies on the altar; in others Artemis rescues her at the last moment and carries her to the land of the Taurians, where years later she is reunited with her brother Orestes.
Adapted from Wikipedia, "Iphigenia" · CC BY-SA 4.0
I.The sacrifice at Aulis
As the Greek fleet gathered at Aulis for Troy, Agamemnon killed a deer in a grove sacred to Artemis (accounts vary). Artemis stayed the winds so the ships could not sail. Calchas announced that Agamemnon must sacrifice his eldest daughter. Under pressure from the army and fellow commanders, he consented.
Iphigenia and Clytemnestra were brought to Aulis under the pretence that Achilles would marry her. In some tellings mother and daughter learn the truth; in others Iphigenia believes she goes to a wedding until the knife. Euripides's Iphigenia at Aulis makes her consent a patriotic act; other versions stress deceit and horror. Clytemnestra's later murder of Agamemnon is widely motivated by this crime.
II.Death or rescue among the Taurians
In some sources Iphigenia dies at Aulis. In others — including Hyginus and Euripides's Iphigenia among the Taurians — Artemis substitutes a deer (or other animal) at the altar and snatches the girl to Tauris (Crimea), where she serves as priestess in a cult that sacrifices strangers.
Years later Orestes and Pylades arrive, sent by Apollo to seize the Taurian image of Artemis. Iphigenia nearly sacrifices them before a recognition scene; they escape together, bringing the cult-statue to Greece. Ritual commemorations and local claims (Attica, Brauron, and elsewhere) attached her name to Artemis cult.
III.Literary reception
Beyond Euripides, Iphigenia appears across epic, lyric, and Roman poetry (including Lucretius's use of the Aulis sacrifice as a critique of religion). She became a staple of opera, ballet, drama, and modern fiction — the daughter whose death (or salvation) opens the Trojan War and seals the fate of the house of Atreus.
Whether she dies or lives as Artemis's priestess remains one of the sharpest forks in the myth: either Clytemnestra's revenge answers a completed murder, or the gods both demand and revoke the human price of the expedition.