‘What you must understand, Aristides,’ Pausanias said at last, ‘is that the people of the Peloponnese are not threatened by Persia. Our wall across the isthmus is complete – a man can walk an hour from one end to the other and find no way past a fortification of stone, three times the height of a man. Gates of iron and Spartan soldiers guard that wall – and the only way in. My own father, Cleombrotus, has overseen the work and deployed the garrison there.’

‘It was Cleombrotus who pledged the support of Sparta against the Persian invasion,’ Aristides said quickly. ‘Your father is a man of honour.’

Pausanias stopped suddenly in the road. His eyes hardened and, for the first time, Aristides thought he was encountering the true man. He held the steady gaze and waited.

‘That oath … was given before the death of my uncle and his personal guard at Thermopylae.’

Aristides knew enough of Spartans to say nothing. He was rewarded by a flush spreading on the regent’s face and neck.

‘Yes, Athenian,’ Pausanias said, inclining his head in mock acceptance. ‘An oath is an oath. We are a pious people.’

‘I have been told so, yes. Then you will be coming out from behind your wall? Winter is not far off, Pausanias. An army the size of the one Xerxes brought will starve unless they gather supplies. There is a moment coming, soon, when they will be low on food. We can bring them to battle then, if you honour the oath your father gave. Will you join us in the field before winter? Will you bring your army out, as was promised?’

‘We did not build a wall just to leave it behind us, Archon Aristides,’ Pausanias replied sharply. He saw Aristides open his mouth to speak and went on. ‘I have not said we will not come. Yet it will not be at the pleading of Athenians, but at the right moment, when we are ready.’

It took the discipline of a lifetime for Aristides not to snap a sharp answer of his own. He bowed his head.

‘I pray it is soon, Regent Pausanias. Not for Athenians, though our need is great, but for all Greece.’

Pausanias waved a hand in the air, as if he brushed away a fly.

‘There is no Greece. There are only cities, like Sparta – and Athens, though I understand it is much reduced.’

There was a spiteful pleasure there and Aristides stood very still.

‘We too swore an oath, Pausanias. To defend the land against a foreign king. We took to the sea – and I have marched eight thousand men to this place in the knowledge that Sparta’s word, once given, would be iron.’