‘Their young warriors blood themselves on us, chasing us through the streets and hills. They beat us and cut us if we even look at them, did you know that? Or they force us to drink too much wine and make us dance for their amusement. We are never freed. Yet … some of us will be free today, I think,’ the man said. ‘My name is Polyemus. Perhaps I will see Athens one day. I would like that.’

The man smiled, but it was a strange, bitter expression. He clapped Aristides on the shoulder, then looked left and right, as if he waited for something. All around, helots were muttering, talking amongst themselves. Aristides had heard them before and not understood they were discussing what to do. The sound was like the sea, or the wind in a stand of trees. Without warning, one of them raised his voice to a parade-ground bellow.

‘Helots! We who are forgotten! We who are dogs! We who are many ! With Sparta watching, shall we remind them?’

A slow roar built, a growl without words that had Aristides turning his head back and forth. These were angry men, or perhaps just men. If they even knew he still watched, in moments they had forgotten him. They talked only to themselves. Another one of them howled like a wolf. He was answered by a thousand throats and as it died back, the sound was mournful, almost unbearable.

‘There is only one freedom for us,’ still another called over their heads, ‘in choosing to stand, in choosing to die. If we say it is so, it is so. We who are forgotten! We who are dogs! We who are many!’

It was taken up as a chant, by thousands, spreading all around them. Aristides had not thought of them at all as he marched out. They had been there like a wall, to make the Persians hesitate. He felt his heart leap as he understood they would fight, with teeth and fists if they had to. They would remind the Spartans they were many, and that they were men. He wondered if Pausanias would still love them then.

Ahead, closer with every pace, the Persian infantry was coming to meet them. Aristides swallowed fear when he saw more men on the field than he had ever seen. They wore panelled coats and carried shields of wicker. They were Mede, Egyptian, Ethiop and Persian trueblood, an ocean wave of soldiers, ready to crash down and drown them all.

Aristides sent a prayer to Athena. He would meet them, with his hoplites out in front of helots, as a bronze spear-tip. He would have to spread them thin to prevent the Persian front curving around like a bull’s horns. Even then, he did not think it would be enough. They were the horizon.