The travellers stopped one night, close to an extensive camp. The nomads showed respect for the paiza of the Khan, and the travellers were invited to stay in a yurt, but they declined, wary of imposing on what might be a fragile hospitality. They sat by their own small fire, eating a bit of mutton and sheep’s tail they had been given by the Mongols, and watched the conquerors of the world at play. The adults wore colourful clothes, trousers, tunics and hats. Their children ran around and shouted and fought as children always did. They seemed to have slaves, plenty of them, skinny-looking folk of Cathay who went barefoot. Mostly the slaves cooked and cleaned, but Avatak glimpsed one girl writing something down, as dictated by her owner. As the night drew in the adults gathered in a circle and danced, and sang, and passed around cups of drink and smoky pipes.

Pyxeas grunted. ‘This dancing, the pipes and the strong stuff they seem to be drinking – this is the old culture, when spirit men would talk to their sky god and the ninety-nine junior deities he controlled. The spirits of the deep steppe, coming back again. When times are hard, people go back to what they know best. The Mongols own half the world, but even they are in thrall to the weather.’

He was dismissive. But something in the way the Mongols celebrated their evening reminded Avatak of home, his own people, nomads too. He said nothing.

‘Once they would not have been here at all,’ Uzzia said. ‘They would have driven their herds to the summer pasture in the hills; it must be too cold up there this year. And they would not have camped in farmland at all; this is not the steppe. But the land is so dry – it is as if the steppe itself is shifting south, and driving the people with it. There will be conflict. Probably there is already. The farmers will lose, of course.’

‘And the city dwellers, in the short term,’ Pyxeas said. ‘But in the long term everybody will lose, when the Mongol empire turns on itself. Once, you know, a khan threatened to obliterate Cathay altogether, and use the land to pasture his herds. Perhaps in time to come – and not very far in the future – that promise will at last be fulfilled. But the irony is that nomadic herders will be far better suited to the conditions that will prevail than city folk, than civilisation.’

‘If war is coming to this place we must press on to Daidu.’

‘Mmm,’ said Pyxeas. ‘And will we find safety there?’

In the morning they moved on once more, working their way ever further east, passing towns and villages and more dried-out farmland. They had to use the scholar’s paiza to get past more layers of guards, more walls thrown across the roads, even this deep into the heart of the country.