In the distance came a group of runners, bare-chested in the summer heat. They had run three laps of the city, some twenty-four miles, before entering the western gate and heading for the centre ground. Ogedai leaned out as far as he could to see them, and for once Guyuk took an interest, craning forward with him, his face alight with excitement. Ogedai glanced at him and wondered if he had wagered some huge sum.

The Mongol people were not long-distance runners as a rule. They had the stamina but not the build, as Temuge had explained it. Some of them limped visibly as they came closer, before trying to hide their weakness as the noise surged around them.

Ogedai nodded to himself when he saw that Chagatai led them. His brother ran smoothly, a head taller than most of the other men. It was true Ogedai feared him, even hated his arrogance, yet he could not disguise his pride at seeing his own brother leading the way into the amphitheatre, pounding up the dusty track to the centre. Chagatai even began to pull away from the rest, but then a small, wiry warrior moved up to challenge him, forcing a sprint when they had nothing left.

As they drew level, Ogedai felt his own heart tremble, his breath coming faster.

'Come on, brother,' he whispered.

At his side Torogene frowned, her hands on the oak bar, gripping it. She had no interest in the man who had nearly killed her husband. She could happily have seen Chagatai burst his heart in front of the crowd. Yet she felt her husband's excitement and she loved Ogedai more than anything in the world.

Chagatai threw himself forward at the last, crossing the line no more than a head's length before the challenger. Both men were close to collapse and Chagatai struggled visibly for breath, his chest heaving. He did not rest his hands on his knees. Ogedai felt a twinge of nostalgia as he remembered his father's words on the subject. If an opponent sees you clinging to your knees, he will think you are beaten. It was a hard voice to escape as they moved on with the years, leaving Genghis behind.

Out of a sense of decency, Guyuk could not cheer his uncle, but his skin glowed with a light perspiration. Ogedai grinned at him, pleased to see his son enthralled for once. He hoped he had won his bet, at least.

Ogedai remained on his feet as the horns sounded once more, spilling a note across tens of thousands. He closed his eyes for an instant, breathing long and slow.

The crowd fell silent.

Ogedai raised his head as his brass-lunged herald bellowed out the words at last.

'You are here to confirm Ogedai, son of Temujin who was Genghis, as khan of the nation. He stands before you as the heir chosen by the great khan. Is there any other who will challenge for the right to lead?'

If there had been silence before, this one had the stillness of death as every man and woman froze, not even daring to breathe as they waited. Guyuk stood back and, for a moment, raised his hand to touch Ogedai's shoulder, before letting it fall without his father knowing.

Thousands of eyes turned towards Chagatai as he stood on the dusty ground with his chest heaving, streaked in sweat. He too looked up at Ogedai on the balcony of oak and his face was strangely proud.

The moment passed and the release of breath was like a summer breeze, followed by a ripple of laughter as people were amused at their own tension and tight expressions.

Ogedai stepped forward, so that they could all see him. The amphitheatre had been influenced by drawings made by Christian monks from Rome who had come to Karakorum. As they had promised, it seemed to magnify sound, so that his voice flew to every ear. He drew the wolf's-head sword and held up the blade.

'I make my own oath before you. As khan, I will protect the people, so that we grow strong. We have had too many years of peace. Let the world fear what will come next.'

They cheered his words and in the enclosed bowl, the sound was immense, almost rocking Ogedai back where he stood. He could feel it on his skin like a physical force. He raised the sword again and they quieted slowly, reluctantly. Down in the field, he thought he saw his brother nod to him. Family was indeed a strange thing.

'Now I will take your oath,' he shouted to his people.

The herald took up the chant: 'Under one khan we are a nation.'

The words crashed back at Ogedai and he gripped the sword tighter, wondering if the band of pressure on his face was his father's spirit. He heart thumped slower and slower until he thought he could feel every beat.

The herald called once more to complete the oath and they replied: 'I offer you gers, horses, salt and blood, in all honour.'

Ogedai closed his eyes. His chest was shuddering and his head felt swollen and strange. A sharp pain made him almost stumble as his right arm buckled, suddenly weak. Part of him expected it to end then.

When he opened his eyes, he was still alive. More, he was khan of the nation, in the line of Genghis. His vision cleared slowly and he took a deep breath of the summer air, feeling himself tremble in reaction. He felt the thirty thousand faces turned to him, and as his strength returned, he raised his arms suddenly in joy.

The sound that followed almost deafened him. It was echoed by the rest of the nation who waited outside the city. They heard and they responded, seeing the torches lit for the new khan. That night, Ogedai walked through the corridors of his palace, with Guyuk strolling at his side. After the excitement of the day, neither man could sleep. Ogedai had found his son throwing bones with his Guards and summoned him for company. It was a rare gesture from father to son, but on that night Ogedai was at peace with the world. Somehow, weariness could not touch him, though he could hardly remember when he had last slept. The bruise on his face had grown colourful. It had been masked for the oath-taking with pale powder, but Ogedai did not know he had streaked it when he scratched his skin.

The corridors became cloisters that opened out onto the palace gardens, still and quiet. The moon was dim behind clouds and only the paths could be seen, as if they walked pale threads through the dark.

'I would prefer to go with you, father, to the Chin lands,' Guyuk said.

Ogedai shook his head. 'That is the old world, Guyuk, a task begun before you were born. I am sending you out with Tsubodai. You will see new lands with him. You will make me proud, I do not doubt it.'

'You are not proud now?' Guyuk asked. He had not meant to ask the question, but it was rare for him to be alone with his father and he spoke his thoughts aloud. To his distress, Ogedai did not answer immediately.

'…Of course, but that is a father's pride, Guyuk. If you intend to follow me as khan, you must lead warriors in battle. You must make them see you are not as they are – do you understand?'

'No, I don't,' Guyuk replied. 'I have done everything you have asked of me. I have led my tuman for years. You saw the bearskin we brought back. I carried it into the city on a lance and the workers cheered me.'

Ogedai had heard every detail. He struggled to recall the words of his own father on the subject.

'Listen to me. It is not enough to lead a pack of young men in a hunt as if it is some great triumph. I have seen them with you, like…dogs, puppies.'

'You told me to choose my officers, to raise them by my own hand,' Guyuk replied.

There was a sulky tone to his voice and Ogedai found himself growing angry. He had seen the beauty of the young men Guyuk had chosen. He could not put words to his unease, but his son's companions did not impress him.

'You will not lead the nation with songs and drunken revels, my son.'

Guyuk came to a sudden halt and Ogedai turned to face him.

'You will lecture me on drinking?' Guyuk said. 'Didn't you tell me once that an officer must be able to match his men, that I should develop a taste for it?'