The whole centre block under Themistocles and Aristides had pulled ahead of the left wing, easing ahead even of the right. Thousands and thousands of Persians were still pouring everything down on their heads, while the Great King’s centre readied themselves to meet them hand-to-hand. Iron swords flashed on the Persian side, catching the sun.

The Immortals were all warriors in their prime, wearing long panelled tunics that reached past their knees. They wore beards in thick braids and clubs, folded and twisted up to make them harder to grab. Gold bands bound their brows, as if each man wore a crown. They used no helmets, but relied on armour and skill with swords. They were the elite soldiers of the empire, the best the Great King could bring to the field. On their own, they numbered as many as the Greek force. Xanthippus felt fear increase as their drums and strange horns began to rattle and whine, the tunes discordant and wrong for that place.

Ahead of him, Greek pipe-players redoubled their efforts. They could not hope to match the volume of the Persians, yet the tune they chose – ‘Athena’ – was taken up by thousands of voices. The Greeks began to sing the promise she had made when the city was founded. It settled and bound them as they trudged forward under a hail of stones and shafts. Xanthippus swallowed, his bloody mouth like sand. He could see more than a few faces turn to see why their left wing had abandoned them. Shields jerked as those in the rear gestured, calling them in.

Epikleos returned to his side, looking flushed. The pace of the slow advance had not altered, so Xanthippus knew the answer before he spoke.

‘Archon Miltiades was unmoved, strategos. He says we are best used as the reserve. Wait for the order to halt and then hold position.’

Xanthippus swore under his breath, surprising his friend. Before he could think of a proper reply, the order came down the line and the left wing was made to halt. Over four thousand stood with Miltiades, drawn clear of the battle as it began. Xanthippus said nothing, firming his resolve. Discipline lay in obeying the archon, in holding the line. Trust was accepting the orders of the one appointed by the Assembly to give them. He thought of his wife and what she would say. Agariste didn’t seem to understand his respect for senior men. She said Miltiades was a fool and that he had wasted a family fortune on silver mines in Thrace – mines that had been lost to the Persian king.

Xanthippus and Epikleos watched in frustration as the Greeks under Themistocles and Aristides lowered spears and locked shields. All the Persian Immortals could see were men of gold: helmets, shields and greaves beneath, spears like a forest of iron leaves.

Xanthippus stared at Miltiades, willing him to give the order to join the attack. With Callimachus absent, the older man stood as if enjoying a debate in the Agora, one foot slightly ahead of the other, his head tilted to one side as he leaned on a spear. His shield was still in the hands of a slave. Xanthippus told himself to wait, to be patient. The orders had been clear. Men of Plataea watched, frowning, not understanding why they had come so far only to stand apart. Xanthippus had to obey, or shame his deme, his tribe – and his wife. Agariste would never forgive him if he came home in disgrace. That much he knew. If the choice was losing his life with dignity and respect, or leaving his honour on the field, he knew she would prefer him to die. He growled under his breath, an animal sound of frustration.