Onomastics Outside the Box brought to my attention that Iphigenia is mentioned in Dante’s Divine Comedy, in Canto V of Paradise. I myself once followed Dante through Inferno and halfway up Purgatory, but never reached Paradise…
I reached for my own copy of Paradise (translation by Mark Musa) but also went searching for the original:
e così stolto
ritrovar puoi il gran duca de’ Greci,
onde pianse Efigènia il suo bel volto,
e fé pianger di sé i folli e i savi
ch’udir parlar di così fatto cólto.
I love the sound of Italian. Canto V says that to make a vow is to surrender a part of your free will to God, and you cannot release yourself from that sacred debt. If necessary, you can – through negotiation with the Church – change the nature of the vow, so long as the new vow surpasses the old.
But let no one assume by his own choice
responsibility for substitution;
be sure the white and yellow keys have turned.
And any change must be considered vain
if the new matter not contain the old,
as six exceeds and holds the number four.
It goes on to say, however, that if keeping a vow means bad things happen, then the vow should not be kept.
better if [Jephthah] had said, ‘My vow was wrong,’
than do far worse by keeping it.
The story of Jephthah is an interesting one, and makes perfect sense in this context. From Judges 11 (New International Version):
30. And Jephthah made a vow to the LORD: “If you give the Ammonites into my hands,
31. whatever comes out of the door of my house to meet me when I return in triumph from the Ammonites will be the LORD’s, and I will sacrifice it as a burnt offering.”
–
34. When Jephthah returned to his home in Mizpah, who should come out to meet him but his daughter, dancing to the sound of timbrels! She was an only child. Except for her he had neither son nor daughter.
35. When he saw her, he tore his clothes and cried, “Oh no, my daughter! You have brought me down and I am devastated. I have made a vow to the LORD that I cannot break.”
36. “My father,” she replied, “you have given your word to the LORD. Do to me just as you promised, now that the LORD has avenged you of your enemies, the Ammonites.
37. But grant me this one request,” she said. “Give me two months to roam the hills and weep with my friends, because I will never marry.”
–
39. After the two months, she returned to her father, and he did to her as he had vowed. And she was a virgin. …
The Canto then gives the sacrifice of Iphigenia by her father – an obvious parallel to Jephthah’s sacrifice of his daughter – as a second example:
No less
insensate was that great war-chief, the Greek
whose Iphigenia mourned her loveliness,
and made the wise as well as simple weep
to hear the tale of such a grievous rite.
Rather than explain what vow Agamemnon supposedly kept, the focus is on Iphigenia weeping over her beautiful face? No, Agamemnon killed his daughter because that was the only way for him to be the leader of the Greek armies. It cheapens the story to have Iphigenia crying, ‘But I’m too pretty to die!’
Francis James Franklin (Alina Meridon) 
The Agamemnon story is largely a story of the conflict that arose when male dominant warrior cultures overtook Mediterranean cultures like Greece. This story says it’s okay for a father to kill his daughter, But not for a wife/mother to seek revenge — because mothers aren’t even related to their daughters (?!) The men win. The women lose.
In Dawn of the Gods, Jacquetta Hawkes discusses the goddess-centric culture of Minoan Crete and the fusion of goddess-culture with the expansion of the patriarchal culture from the Steppes in Bronze Age Mycenaean Greece. It’s a long time since I read it, but she has an interesting note at the end about the roles of women in Classical Greece (centuries after the Trojan War), ending with:
“I am not being so foolish as to deny that in many ways Greek society was very masculine. It was conceded in the opening chapter that in the marriage of cultures the Achaean tradition tended to dominate – and this was more true in social patterns than in cultural life. It showed itself, alas, nowhere more plainly than in the Greeks’ dedication to warfare. In this their natural instincts were greatly encouraged by their ancient educator, Homer.”
The sacrifice of Iphigenia has never been seen as justified, only as a necessary evil. Agamemnon is never portrayed as a hero. No one can doubt his power and wealth, but he is arrogant, ambitious and cowardly. To get Iphigenia to the altar he has to lure her there with trickery, pretending that she is to marry Achilles.
‘My father, father!’ – she might pray to the winds;
no innocence moves her judges mad for war.
Her father called his henchmen on,
on with a prayer,
‘Hoist her over the altar
like a yearling, give it all your strength!
She’s fainting – lift her,
sweep her robes around her,
but slip this strap in her gentle curving lips…
here, gag her hard, a sound will curse the house’ –
and the bridle chokes her voice… her saffron robes
pouring over the sand
—Aeschylus, Agamemnon, trans. Robert Fagles
And when he eventually gets home again, ten years or so later, a wrathful Clytemnestra takes her revenge.