‘Cimon! Don’t just nod at me. I need to know you have understood.’ With an effort, Xanthippus gentled his tone. ‘I had experience of Spartans when I lived in Corinth. I know them well enough, better than most. So, I will take the lead. Look to me and make no observations of your own. Do you understand?’

‘Of course I understand,’ Cimon snapped.

If they had not been approaching a Spartan fortress wall, Xanthippus would have reined in and taken him to task for his anger. It was as dangerous as a drawn sword in that place.

With Spartans watching them, Xanthippus could only ignore the lack of courtesy, his lips a pale line. Xanthippus had spoken as much for the ears of the other two, Relas and Onesimos. They gaped like farmers in the Agora until he cleared his throat. None of them had ever seen the finished Spartan wall, built across the isthmus. It stretched from coast to coast, an hour’s march one end to the other – three times the height of a man and strong, Xanthippus could see that. Beyond it, the entire Peloponnese peninsula was hidden from view except as distant mountains – cities of Corinth, Sparta and Argos; Arcadia, ancient home of the god Pan; Elis, where the games at Olympia were held to honour Zeus! All that was cut off from the heartlands that year. It seemed a bitter irony to Xanthippus. He had come from a city without walls, that wanted them, to a wall raised by men who scorned the very idea.

Spartan guards stood on the wall’s crest. They had not donned their helmets and carried no shield or spear. Each of them wore the famous red cloak that would wrap him against the night’s cold. Some went naked underneath, or wore only a kilt and sandals. Xanthippus endured the insolence of their stares as he dismounted, still a good thirty paces from the wall itself.

The road was well worn there, but there was no sign of any other travellers trying to get through. The closest gate was clearly shut, a solid-looking thing. Xanthippus was wondering how best to approach when they lowered a man down, his foot in a loop of rope. Xanthippus eyed his companions.

‘Say nothing, any of you,’ he muttered once again. ‘They’ll be wary with a Persian army in range. Our business lies beyond this wall.’