Not having been let in on the truth, Clytemnestra (Adjoa Andoh) is at first mainly worried that at ten years old her daughter is too young for an arranged marriage to Achilles, and seeks reassurances that the arrangement will remain purely symbolic until she's old enough. So we get to see the full shock and horror as the truth is revealed and her husband Agamemnon (Patrick O'Kane) casually murders Iphigenia in a religious ritual. Ten years later, having finally won the war the sacrifice was for, he returns with little contrition.
For those familiar with the Oresteia there's a lot of interesting alternatives that Carr explores; most obviously, in Aeschylus the murder of Agamemnon has been decided long before his return home and takes place soon after, but almost the entirety of Girl on an Altar takes place in that time - Carr gives us a diversion to a nightmarish harem where forgotten concumbines are sent to die, and she even squeezes an entire battle between the return and the murder. Agamemnon's death isn't a given at first, and despite their bitterness this is a story where reconciliation is a possibility, until his arrogance and lack of remorse send them down a path of no return. Surprisingly, jealousy is a major factor early on - Agamemnon's for Clytemnestra's affair with Aegisthus (Finbar Lynch,) and even Clytemnestra's for her husband's new lover (Ayesha Antoine as a much more lucid Cassandra than we usually see in the story.)
Also interesting is Clytemnestra's supportive but pragmatic slave Cilissa (Sharon Duncan-Brewster,) who while not diminishing the tragedy of Iphigenia's death does reflect on the fact that this is a time when many children die (two other girl sacrifices are casually alluded to) but it's only regarded as horrific when it's the child of a queen; it's implied her own children were all killed, but as a slave she doesn't get tragedies written about her. In the second act there's also a focus on how Clytemnestra's father Tyndareus (Joseph Mydell) has been a kingmaker to Agamemnon and could be crucial in that role again now. Perhaps most striking to me is the focus on this as a story without gods despite being built on sacrifices to them. Agamemnon is almost openly an atheist, admitting the sacrifice of Iphigenia was mainly about showing himself ruthless to keep his position as king-of-kings in the Greek alliance. As the repeated references to him as "Zeus Agamemnon" testify, this isn't a story about appeasing the gods, but becoming them.
On the downside is the play's storytelling style, which like Hecuba takes Greek tragedy's "tell don't show" approach to the extreme with a lot of soliloquies and the characters narrating the action; once again it's a technique that's fascinating at first but hard to keep interested in, despite the cast's efforts to bring real emotion into a highly stylised form. To me Girl on an Altar is one of those contradictory experiences that tried my patience a bit while watching it, but will probably have me thinking back to its twists on the mythology for some time to come.
Girl on an Altar by Marina Carr was presented online by the Kiln Theatre.
Running time: 2 hours 5 minutes including interval.