'So I would suppose,' Iphigeneia said. 'What else should we do? They will hardly want us to go to Troy with them.'

Sisipyla looked down, conscious that she had been in some way sloppy and unfocussed again. From the moment she had heard of the proposal it had been her consolation that they would return, that Iphigeneia would not be taken from her. Achilles would go away to the war. People said the war would be over in no time once the army got there, but it might take much longer than anyone thought. And then, anything could happen in a war. Meanwhile, she and Iphigeneia would return here and life would go on as before. In her gratitude for this, she had not much considered the feelings of Achilles, except to think it strange that a wind coming from the wrong direction should be the cause of his offer; he could not have intended it when he set out. Being forced to wait there, she thought vaguely, the desire of his heart had risen to the surface – she saw it as a silver fish in a dark pool, glimmering up to the light. And Iphigeneia had accepted, without a moment's hesitation, in just one scoop...

'You have no doubts,' she dared to say now, in the tone of a question, and saw an immediate shadow come to Iphigeneia's face. 'Doubts? Apart from being famous and well-connected and fantastic-looking, Achilles is one of the richest men in Greece. Did you know that? No, you didn't, I can tell. He is a copper magnate, he owns at least six copper mines in the region of Lamia. But that's not the main thing, not for me anyway. Through his mother he enjoys special protection and my family are in great need of that protection. There is a curse on us. You don't know the story of the House of Atreus, do you?'

'Well...'

The shadow on Iphigeneia's face deepened. 'You can't possibly know it. No one outside the family knows it. No one is allowed to speak of it. It is not known to any singer. I learned of it by accident, when I was very little, before the time I was due to be told.'

The quantity of things Iphigeneia herself didn't know still sometimes surprised Sisipyla. The story was common knowledge, a matter of gossip, not only among the servants of the palace, the sweepers and washerwomen, but even in the town below the walls, among those who came with eggs and honey and cheese to sell. 'I would very much like to hear the story,' she said.

'Promise you won't tell anyone.'

'I promise.'

'The founder of the line was Tantalus and he had three children, Pelops, Niobe and Broteas. He got this idea of testing the omniscience of the gods. You don't know that word, do you? No, it's no use, I can tell from your face that you don't. It means knowing everything that there is to know. Tantalus invited the gods to a feast and he served them with his own son Pelops.'

She paused a moment, looking sternly at Sisipyla. 'All mashed up in a stew, you know, and heavily disguised with spices, so no one should know what they were eating. It was his idea of a joke. Well, he was obviously unhinged. Of course, the guests saw through this trick at once, all but Demeter, she absent-mindedly ate a piece of one shoulder. They were all highly offended, in fact they were furious. Well, wouldn't you be? They condemned Tantalus to starve and thirst in Hades for ever, with all sorts of delicious things just out of his reach. That is where he is now, at this moment, all chained up.'

Iphigeneia remained silent for some moments and Sisipyla saw that she was waiting for a question to spur the narrative forward. 'That was the end of Pelops then?'

'No, they brought Pelops back to life.'

'That must have been a difficult job when he was all chopped up like that. What about that shoulder?' She had not heard about the shoulder before and it had appealed to her imagination. 'How could they put his shoulder in place when it had been partly eaten?'

'I've really no idea,' Iphigeneia said impatiently. 'You always seem to fasten on these unimportant details. Pelops went to another part of the country, Pisa, on the borders of Elis, and got married there to someone called Hippodameia. Her father didn't want anyone to marry her. I think he was, you know, keen on her himself. So Pelops had to kill him.'

'How did he do that?'

'He bribed the king's charioteer, whose name was Myrtilus, to take the wooden pins out of one of the chariot wheels and put wax ones there instead. He promised Myrtilus half the kingdom and a night in bed with Hippodameia. Then he got into some sort of chariot race with the king and the wheel fell off and the king was thrown out and got entangled in the reins and Pelops killed him and then galloped away with Hippodameia by his side.'

'What about Myrtilus?'

'Well, of course, he lost no time in claiming his reward. But Pelops had no intention of keeping his promises now he had got what he wanted. He lured Myrtilus on to a boat and pushed him overboard somewhere near the harbour of Elis. Before he drowned this charioteer invoked a curse on the descendants of Pelops. This was the first curse that was put on our family, and it soon started to take effect. Pelops and Hippodameia had two sons, Atreus and Thyestes. Atreus was the rightful king of Mycenae but Thyestes tried to get the throne from him, so they quarrelled, but then Atreus pretended that he wanted to make it up and he invited his brother to dinner.'

Iphigeneia widened her eyes and stared solemnly at Sisipyla. 'Guess what happened then,' she said. 'He did exactly the same thing, except that it was not his own children but his brother's three sons that he killed and served up to their father in a stew. It was history repeating itself.'

'Three sons,' Sisipyla said. 'It must have been an enormous meal.'

'When Thyestes had finished, Atreus showed him the heads and hands of his children, you know, just to drive the point home. Thyestes laid a curse on Atreus and his descendants then fled into exile, taking his remaining son Aegisthus with him. That was the second curse. It is the same Aegisthus who has turned up again now and is being entertained by my mother as a guest here. No one knows where his father is. Someone sent a messenger to Atreus to say Thyestes had been killed – the man had a bloodied sword to prove it. Atreus was delighted. He went off alone to make a thanksgiving sacrifice and he was found dead next day with stab wounds all over him. Nobody knows who did it. The messenger couldn't be found. Atreus had two sons, Agamemnon and Menelaus, my father and my uncle. That curse is still lying on them and all of us.'

Sisipyla nodded. There were voices that named Aegisthus himself as the killer of Atreus, but she said nothing of this. Lots of stories went round. There were even those who said that Thyestes had raped his own daughter, Pelopeia, and that Aegisthus was the child of this rape. She saw from Iphigeneia's fixity of expression and the thinning of her mouth that the princess had been affected by the grim story in telling it. It was hard to think of words of comfort. 'It's always the children who suffer, isn't it?' she said.

'That's one thing,' Iphigeneia said. 'The other is tricks. Did you notice? These two things run through all the story. A chariot race, a boat trip, an invitation to dinner, a sword with blood on it. There's always a trick, and the trick always ends in a murder.'

Sisipyla felt a return of anxiety about the sacrifice due soon to take place. It was late, darkness was falling. Those with parts to play in the procession would be already assembling in the courtyard below the main staircase. She and Iphigeneia would have to start getting ready soon. 'What was the accident?' she said.

'Accident?'

'You said you only learned the story by accident.'

'Oh yes, it was told me by a nurse when I was very little, before you came. She told me stories while she was bathing me and getting me ready for bed. All kinds of stories, but this was her favourite. Heaven knows how she found out about it. She had these huge eyes – or so they seemed to me then. She must have known she was frightening me. She made it seem like a secret, something just between the two of us; but I had nightmares, I used to wake up screaming, and so it all came out.'