Surely the Greeks had rowed and fought to complete exhaustion. It had been hard to see if they suffered as much as his own captains. When they’d formed up in three great spears, the battle had grown ugly, like fishermen drawing a trident through the waters. They’d become more skilful and more sure before his very eyes, scattering his fleet in blood and scales. He owed them vengeance, by the grace of Ahura Mazda, by the love of angels, he did.

It was not over, he told himself, though terrible despair gnawed at him. If dawn brought the second part of his fleet coming up the strait, the Greeks might still surrender. Xerxes had imagined mercy for them then, when he had discussed it with Mardonius. Perhaps they had fought too hard against the collar for that. When a dog bites the hand that grips it by the neck, it is hard not to batter down its resistance, with force and rage so great it either dies or submits. Xerxes felt the need for that, a fantasy of vengeance growing in him like tendrils unfurling. He would certainly burn their ships and the crews on them. Once they had surrendered. He would do it for the education of those who watched from the hills and sandbanks of Salamis. The king had seen them all day across the strait, waving their arms in support, urging their men on. It had been an unforgivable display, without dignity. He thought of making an example of their women and, to his surprise, felt arousal stir. The sensation faded as quickly as it had come, leaving him cold and numb.

Like a child gorged on honey, Xerxes had grown sick of sweetness. Only the thought of seeing his enemies crushed could intoxicate him now, dreams so vivid they might even banish the real world.

He paused in his thoughts, though it was like throwing a rein on a wild horse. He scowled at the sight of Mardonius approaching. Under moonlight, his general marched along the sand with two of the king’s guards and the slender figure of the herald flanking him. The small group prostrated themselves as if they had been struck dead. Xerxes waited just a beat, then bade them rise.

‘Our ally in the fleet has sent another letter, Majesty,’ Mardonius said. ‘I’m afraid your guards killed the messenger, thinking him a spy or an assassin. They brought me the package he carried, however. I am sorry, Highness, Great King. I have had the men responsible taken to be whipped.’

Whatever irritation Xerxes might have felt vanished at the news.

‘Don’t be too hard on them,’ he said expansively. ‘My safety is their first duty. I would rather they reacted with too much vigour than too little.’

‘Your mercy is infinite, Majesty. Thank you.’