(Ἰφίγενεια), according to the most common tradition, a daughter of Agamemnon and Clytaemnestra (Hyg. Fab. 98), but, according to others, a daughter of Theseus and Helena, and brought up by Clytaemnestra only as a fosterchild. (Ant. Lib. 27; Tzetz. ad Lycoph. 183.) Agamemnon had once killed a stag in the grove of Artemis, or had boasted that the goddess herself could not hit better, or, according to another story, in the year in which Iphigeneia was born, he had vowed to sacrifice the most beautiful thing which that year might produce, but had afterwards neglected to fulfil his vow. Either of these circumstances is said to have been the cause of the calm which detained the Greek fleet in the port of Aulis, when the Greeks wanted to sail against Troy. The seer Calchas, or, according to others, the Delphic oracle, declared that the sacrifice of Iphigeneia was the only means of propitiating Artemis. Agamemnon at first resisted the command, but the entreaties of Menelaus at leagth prevailed upon him to give way, and he consented to Iphigeneia being fetched by Odysseus and Diomedes, under the pretext that she was to be married to Achilles. When Iphigeneia had arrived, and was on the point of being sacrificed, Artemis carried her in a cloud to Tauris, where she was made to serve the goddess as her priestess, while stag, or, according to others, a she-bear, a ball, or an old woman, was substituted in her place and sacrificed. (Eurip. Iphig. Taur. 10-30, 783, Iphig. Aul. 1540, &c.; Welcker, Die Aeschyl. Trilog. p. 408. &c.; Suid. s. v. Πενθερός According to Dictys Cretensis (1.19, &c.), Iphigeneia was saved in a peal of thander by the voice of Artemis and the interference of Achilles, who had been gained over by Clytaemnestra, and sent Iphigeneia to Scythia. Tzetzes (l.c.) even states that Achilles was actually married to her, and became by her the father of Pyrrhus.

While Iphigeneia was serving Artemis as priestess in Tauris, her brother Orestes, on the advice of an oracle, formed the plan of fetching the image of Artemis in Tauris, which was believed once to have fallen from heaven, and of carrying it to Attica. (Eur. IT 79, &c.) When Orestes, accompanied by Pylades, arrived in Tauris, he was, according to the custom of the country, to be sacrificed in the temple of the goddess. But Iphigeneia recognised her brother, and fled with him and the statue of the goddess. Some say that Thoas, king of Tauris, was previously murdered by the fugitives. (Hyg. Fab. 121; Serv. ad Aen. 2.116.) In the meantime Electra, another sister of Orestes, had heard that he had been sacrificed in Tauris by the priestess of Artemis, and, in order to ascertain the truth of the report, she travelled to Delphi, where she met Iphigeneia, and was informed that she had murdered Orestes. Electra therefore resolved on putting Iphigeneia's eyes out, but was prevented by the interference of Orestes, and a scene of recognition took place. All now returned to Mycenae; but Iphigeneia carried the statue of Artemis to the Attic town of Brauron near Marathon. She there died as priestess of the goddess. As a daughter of Theseus she was connected with the heroic families of Attica, and after her death the veils and most costly garments which had been worn by women who had died in childbirth were offered up to her. (Eur. IT 1464; Diod. 4.44, &c.; Paus. 1.33.) Pausanias (1.43), however, speaks of her tomb and heroum at Megara, whereas other traditions stated that Iphigeneia had not died at all, but had been changed by Artemis into Hecate, or that she was endowed by the goddess with immortality and eternal youth, and under the name of Oreilochia she became the wife of Achilles in the island of Leuce. (Ant. Lib. 27.) The Lacedaemonians, on the other hand, maintained that the carved image of Artemis, which Iphigeneia and Orestes had carried away from Tauris, existed at Sparta, and was worshipped there in Limnacon under the name of Artemis Orthia. (Paus. 3.16.) The worship of this goddess in Attica and Lacedaemon is of great importance. At Sparta her image was said to have been found in a bush, d to have thrown the beholders into a state of madness; and once, as at the celebration of her festival, a quarrel arose which ended in bloodshed, an oracle commanded that in future human sacrifices should be offered to her. Lycurgus, however, is said to have abolished these sacrifices, and to have introduced in their stead the scourging of youths. (Paus. 3.16.6; Dict. of Antiq. s. v. Diamastigosis.) That in Attica, also, human sacrifices were offered to her, at least in early times, may be inferred from the fact of its being customary to sled some human blood in the worship instituted there in honour of Orestes. (Eur. IT 1446, &c.)

Now, as regards the explanation of the mythus of Iphigeneia, we are informed by Pausanias (2.35.2) that Artemis had a temple at Hermione, under the surname of Iphigeneia; and the same author (7.26) and Herodotus (4.103) tell us, that the Taarians considered the goddess to whom they offered sacrifices, to be Iphigeneia, the daughter of Agamemnon. From these and other circumstances, it has been inferred that Iphigeneia was originally not only a priestess of Artemis, or a heroine, but an attribute of Artemis, or Artemis herself. For further explanations, see Kanne, Mythol. p. 115, &c.; Müller, Dor. 2.9.6; Schwenk, Etym. Mythol. Andeut. p. 218; G.Meyer, De Diana Taurica Dissert. Berlin, 1835.