As the sun set, the brothers pushed the last boat into the calm water, wading in after it and clambering over the sides. Jelaudin raised the small sail and caught the breeze, the moment strangely reviving to his spirits. They left their horses behind and the fishermen took the reins in astonishment, still yelling curses after them, though the animals were worth far more than the crude boats. As the breeze freshened, Jelaudin took his seat and pushed the rudder down into the water, tying off a rope that held it in place. In the last light, they could see the white line of breaking waves on a small island out on the deep. He looked down at his father as he set their course and felt numb calm steal over him as he left the land behind. He could not last much longer and it was true the old man deserved a peaceful death.

The name Samarkand meant ‘town of stone’ and Genghis could see why as he gazed on its buttressed walls. Of all the cities he had known, only Yenking was more of a fortress and he could see the minarets of many mosques towering behind the walls. Built on the flood plain of a river running between huge lakes, it was surrounded by the most fertile soil Genghis had seen since coming to Arab lands. He was not surprised to find Shah Ala-ud-Din had made the place his jewel. There was no dust or sand there. The city was a crossroads for merchant caravans travelling thousands of miles, secure in the protection it gave them. In times of peace, they trundled across the plains, bringing silk from the Chin and collecting grain at Samarkand to take even further to the west. There would be no more of that trade for a time. Genghis had broken the line of cities that supported each other and grew rich. Otrar had fallen, then Bukhara. To the north-east, he had sent Jelme, Khasar and Kachiun to batter other cities into submission. He was close to obliterating the spine of the shah’s trade routes. Without trade and messages, each city was isolated from the others and could only suffer as they waited for his warriors. While the shah still lived, it was not yet enough, nor even close to enough.

In the distance, Genghis could see white smoke rising into the air from the last of the trading caravans to have tried reaching Samarkand before he entered the area. No more would come now, not until the Mongols had moved on. Once again, he considered Temuge’s words on the need to establish more permanent rule. The concept intrigued him, but it remained a dream. Yet he was no longer a young man and, when his back ached in the mornings, he would think of the world running on without him. His people had never cared about permanence. When they died, the troubles of the world slipped away from them. Perhaps because he had seen empires, he could imagine one lasting beyond his life. He enjoyed the thought of men ruling in his name, long after he had gone. The idea eased something in him that he hardly realised was there.

As Genghis watched, the tumans of Jochi and Chagatai rode back from the city walls, having spent the morning riding close enough to terrorise the population. They had raised a white tent before Samarkand when the siege was in place, but the gates had remained closed. In time, they would replace it with a red one and then the black cloth that signified the death of all those within.

With the shah gone, the Arabs had no one to organise the defence of Khwarezm and each of his cities fought alone. Such a state of affairs suited Genghis very well. While the cities sweltered in fear, he could bring two or three tumans to bear on a single point, breaking the resistance and moving on to the next with only death and fire behind them. This was war as he preferred it, the breaking of cities and small garrisons. His Arab interpreters claimed that half a million people lived inside the walls of Samarkand, perhaps more now that the farms were empty all around. They had expected him to be impressed, but the khan had seen Yenking and he did not let the numbers trouble him.

He and his men rode with impunity and those who lived behind stone could only wait and fear. It was hard to imagine choosing that sort of life over the ability to move and strike where he pleased, but the world was changing and Genghis struggled with new concepts every day. His men had ridden as far as the frozen wastelands in the north and Koryo in the east. He considered those lands conquered. Yet they were far away. They would rebuild and forget they owed tribute and obedience to him.

He pursed his lips at the thought of city-dwellers making new walls and burying their dead. That thought did not sit well with the khan of the Mongols. When he knocked a man down, he stayed down, but a city could rise again.

He thought of Otrar then, of the wasteland he had left behind him. Not one stone had been allowed to sit on another and he did not think there would be a city there again, even in a hundred years. Perhaps to kill a city, you had to dig the knife in deep and wrench it back and forth until the last breath escaped. That too was a prospect that pleased him.

As he rode slowly around Samarkand, Genghis’ thoughts were interrupted by the thin notes of warning horns. He reined in, jerking his head back and forth to hear the sound more clearly. Jochi and Chagatai had heard, he could see. Between Genghis and the city, they too had come to a halt to listen.

In the distance, Genghis could see scouts riding in at full gallop. The horns had been theirs, he was almost certain. Could there be an enemy in sight? It was possible.

As his mount reached down to wrench a mouthful of dry grass, Genghis saw the gates of Samarkand swing open and a column ride out. He showed his teeth, welcoming the overconfidence of the enemy. He had Jebe’s tuman as well as ten thousand of his own veterans. Between those and the tumans of Jochi and Chagatai, they would crush any army Samarkand could vomit at them.

The scouts reached Genghis, their horses almost dead under them from the manic ride.

‘Armed men to the east, lord,’ the first one called before two of his companions. ‘As many as three tumans of Arab warriors.’

Genghis swore softly. One of the other cities had responded to Samarkand after all. Jochi and Chagatai would have to meet them. He made his decisions quickly, so that his warriors saw only certainty in his responses.

‘Ride to my sons,’ Genghis said to the scout, though the young warrior still panted like a dog in the sun. ‘Tell them to attack this enemy to the east. I will hold against whatever Samarkand can bring to the field.’

The tumans of his sons moved quickly away, leaving Genghis with just twenty thousand men. His lines formed with the khan at the centre of a shallow crescent, ready to move easily into enveloping horns.

More and more riders and men came out of the city, almost as if Samarkand had been a barracks for a wing of the shah’s army. As Genghis moved his mount into a slow trot and checked his weapons, he hoped he had not sent too many warriors away to take the victory. It was possible, but if he attacked only one city at a time, it would be the work of three lifetimes to subdue the Arab lands. The cities of the Chin had been even more numerous, but he and his generals had taken ninety in a single year before reaching Yenking. Genghis had ridden against twenty-eight of them.

If Tsubodai or Jebe had been there, or even Jelme or one of his brothers, he would not have worried. As the plain blackened with roaring Arabs, Genghis laughed aloud at his own caution, making the warriors around him chuckle. He did not need Tsubodai. He did not fear such enemies, nor a dozen armies like them. He was khan of the sea of grass and they were just city men, soft and fat for all their bluster and sharp swords. He would cut them down.