Genghis looked up in surprise, then smiled slowly at the sight of the wiry old man on the edge of the training ground. Arslan was darkly tanned and as thin as a stick, but the sight of him was a pleasure Genghis had not expected again.

The khan cast a glance at his opponent who stood barely breathing hard, his sword ready.

‘I am hoping to surprise this young tiger when he turns his back,’ he said. ‘It is good to see you. I thought you might have been content to stay with your wife and goats.’

Arslan nodded.

‘The goats were killed by wolves. I am no herdsman, it seems.’ He stepped onto the stone square and took Genghis’ arm in a familiar grip, his eyes weighing the changes in the khan.

Genghis saw that the old general was marked with thick dust from months of riding. He pressed his grip tighter, showing his pleasure.

‘Eat with me tonight. I want to hear about the plains of home.’

Arslan shrugged.

‘They are the same. From west to east, Chin merchants do not dare cross your land without asking permission from one of the road stations. There is peace there, though there are fools who say you will not return, that the shah’s armies are too much even for you.’ Arslan smiled at the memory of a Xi Xia merchant and how he had laughed in his face. Genghis was a hard man to kill and always had been.

‘I want to hear it all. I will invite Jelme to eat with us,’ Genghis said.

Arslan brightened at word of his son.

‘I would like to see him,’ he replied. ‘And there are grandchildren I have not seen.’

Genghis winced slightly. Tolui’s wife had given birth to her second son within a few months of Chagatai’s first-born. He was a grandfather three times over, though part of him was not at all thrilled at the idea.

‘My sons are fathers now,’ he said. ‘Even little Tolui has two baby boys in his ger.’

Arslan smiled, understanding Genghis better than he knew.

‘The line must go on, my friend. They too will be khans one day. What did Tolui call them?’

Genghis shook his head, amused at Arslan’s fatherly interest.

‘I named the first Mongke. Tolui called the second Kublai. They have my eyes.’

It was with an odd sense of pride that Genghis showed Samarkand to the man who would rule the city. Arslan was fascinated by the water system and the markets, with their intricate web of suppliers from a thousand miles all around. By then, Genghis had discovered the gold mines that fed the shah’s treasury. The original guards had all been killed and the mine looted by the time he realised its significance on the maps, but he had new men working and some of his brightest young warriors learning the process of taking gold and silver from the ground. That was one benefit of the city, he had found. It supported more men than the life he had known on the plains. Those men could be used to build other things, perhaps even greater.

‘You will have to see the mine,’ Genghis told Arslan. ‘They have dug into the ground like marmots and built great forges to separate the silver and gold from the rock. More than a thousand men dig and half as many again crush the rock into powder. It is like a nest of ants, but from it comes the metal that makes this city run. Everything else works from that. At times I feel I am very close to understanding how they came to have value. It feels like a thing built on lies and promises, but it works, somehow it does.’

Arslan nodded, watching Genghis rather than listening too closely to things he could not have cared less about. He had answered the call because he knew Genghis would not have summoned him without reason. He had yet to understand why the cities had suddenly become important to the younger man. For two days, he walked with Genghis through Samarkand, talking and taking note of the khan’s inner tension. Arslan’s wife had been given a suite of rooms in the palace and seemed entranced with the great baths and Chin slaves Genghis had procured for her. It interested Arslan to note that neither of Genghis’ wives had left the camp of gers outside the city.

On the third day at noon, Genghis stopped by a market, taking a seat on an old bench with Arslan. The stalls were busy, their owners nervous at the presence of the Mongols in their midst. Both men sat comfortably, waving away those who came to offer them fruit juices or salted bread and meat.

‘Samarkand is a fine city, Genghis,’ Arslan said. ‘But you did not care about cities before. I have seen you staring out to the camp of gers every time we walk the walls and I do not think you will stay here much longer. Tell me then why I should.’

Genghis hid a smile. The old man had not lost his sharpness in the years apart.

‘I thought for a time that I would take cities for my people, Arslan. That this would be our future.’ He shook his head. ‘It is not, at least for me. The place has beauty, yes. It is perhaps the finest rats’ nest I have ever seen. I thought if I could truly understand the way it works, perhaps I could rule from a city and spend my final days in peace, while my sons and grandsons conquer.’ Genghis shivered as if a breeze had found his skin. ‘I cannot. If you feel the same way, you may leave and go back to the plains with my blessing. I will destroy Samarkand and move on.’

Arslan looked around him. He did not like being surrounded by so many people. They were everywhere and for a man who had spent much of his life on open plains with just his son or a wife, their closeness made him uncomfortable. He suspected Samarkand was no place for a warrior, though it may have been a place for an old man. His wife thought so, certainly. Arslan was not sure if he could ever feel at ease there, but he sensed Genghis was reaching for something and struggled to understand.

‘You only cared about razing cities once,’ he said at last.

‘I was younger then,’ Genghis replied. ‘I thought a man could throw his best years against enemies and then die, feared and loved, both.’ He chuckled. ‘I still think that, but when I am gone, the cities will rebuild and they will not remember me.’

Arslan blinked to hear such words from the great khan he had known almost from boyhood.

‘What does that matter?’ he asked incredulously. ‘You have been listening to Temuge, I think. He was always chattering about the need for history, for records.’

Genghis cut the air with his hand, impatient with the way the discussion was going.

‘No, this is from me. I have fought all my life and I will fight again and again until I am old and feeble. Then my sons will rule lands even greater and their sons after them. That is the path we made together, Arslan, when I had nothing but hatred to sustain me and Eeluk ruled the Wolves.’

He saw Arslan’s astonishment and went on, searching for the words to give voice to his hazy ideas.

‘The people of this city do not hunt to eat, Arslan. They live longer than we do and it is a softer life, yes, but there is no evil in that alone.’

Arslan snorted, interrupting him without caring for the blaze of anger it provoked. It had been a long time since anyone broke in while Genghis was speaking, even in his closest family.

‘Until we come and kill their kings and shahs and knock their walls down,’ Arslan said. ‘Of all men, you have shown the weakness of cities and you would now embrace them? Perhaps you will build statues to yourself like the ones by the walls. Then every man can look on the stone face and say, “That was Genghis.” Is that it?’

The khan had gone very still as Arslan spoke and the fingers of his right hand drummed silently on the wooden bench. He sensed danger radiating off Genghis, but Arslan did not fear any man and he refused to be cowed.

‘All men die, Genghis. All. Think what it means for a moment. None of us are remembered for more than one or two generations.’ He raised a hand as Genghis opened his mouth to speak again. ‘Oh, I know we chant the names of great khans by the fireside and the Chin have libraries running back for thousands of years. What of it? Do you think it matters to the dead that their names are read aloud? They don’t care, Genghis. They are gone. The only thing that matters is what they did while they were alive.’