He sent for his generals and they came to his ger before the sun set.

‘These are my orders,’ Genghis told them. ‘I will remain with one tuman to protect the families. If they come for me here, I will be ready for them. You will go out in all directions. Find me anything about these Assassins and come back. Rich men can hire them, so you will have to break wealthy towns and cities to get at those men. Take no prisoners except the ones who claim to know something. I want the location.’

‘News of a bribe will spread as fast as we can ride,’ Tsubodai said. ‘We have cartloads of gold and jade and this could be a use for it. With your permission, lord, I will also promise some great sum to anyone who can tell us where the Assassins train. We have enough to tempt even princes.’

Genghis waved a hand, accepting the idea.

‘Offer to spare cities that bring us the information if you want. I do not care how it is done, just get the information I need. And take the Arabs in the camp with you. I don’t want them anywhere close until we have met and destroyed this threat. Nothing else matters until then. The shah is dead, Tsubodai. This is the only threat we face.’

Jelaudin felt the crowd surge as if he held their hearts in his hand. He had them hanging on his words and the feeling was as intoxicating as it was new. In his father’s army, he had dealt with men already sworn to obedience. He had never had to recruit them, or persuade them to his cause. To find he had that skill, that he had a genius for it, had surprised him almost as much as his brothers.

He had begun by visiting mosques in the Afghan towns, small places with just a few hundred of the devout. He had spoken to the imams of those places and relished the horror they showed when he told them of Mongol atrocities. He had learned what worked then and the tales grew wilder with each telling. He had come away from the very first village with forty strong men of the Pathan tribe. Until he had arrived in their midst, they had not even known the infidels had invaded Arab lands, never mind that they had killed the Shah of Khwarezm. Their righteous anger had surprised Jelaudin at first, until he saw it echoed in every village and town he visited. The numbers of loyal men had grown and more than two thousand sat outside in the dust, waiting for the charismatic leader they had vowed to follow.

‘With my own eyes,’ he said, ‘I saw the Mongols destroy a mosque. The holy men raised empty hands to stop them, but they were killed and tossed aside, their bodies left to rot.’

The crowd murmured angrily, the largest he had addressed since coming south. Most of them were young men and there were many boys with them, their heads bare of the turbans the older men wore. Jelaudin had found the young were the ones he reached first, though they brought experienced warriors in from the hills to hear him speak. If his father had lived, Jelaudin thought the shah might have tried the same, but his death was the perfect event to have strong men taking up their swords. He spoke with passion of the foreigners who laughed at the faith and despoiled the holy places. They drank in his words. Jelaudin raised his hands to quieten them and they fell silent, gazing on him with perfect attention. He had them.

‘I saw our women and children killed and taken by their warriors, torn from the hands of their husbands. Those who wore veils were stripped and abused in public. In Bukhara, they killed an imam on the steps of the blue mosque and their young men urinated on the body. I would tear out my eyes for what they have seen, if I did not need them for Allah’s vengeance!’

Many in the crowd surged to their feet, overcome with rage and excitement. They raised their swords and jabbed them into the air, chanting holy words of war. Jelaudin turned to exchange a glance with his brothers and found them already on their feet and roaring with the rest. He blinked at that, hardly expecting them to be so affected by his words. Yet they too drew swords and their eyes were bright with anger. They had seen all that Jelaudin had seen, but still the words, the hot, lifeless air, the need fired their blood. Even Tamar began to chant with the warriors of Islam, intoning the words of the prophet. Jelaudin’s heart swelled as the noise crashed over him. Had his father known of this? He felt as if he was balancing a sword. If it slipped, he would lose everything, but the weight of their belief brought reality to his dreams. Already men were coming to him as word spread throughout the region. He had called for a holy war on the Mongol aggressor and his words and promises had set the land alight. Imams preached in mosques he had never seen that he was a warrior of God. His task was merely to feed that fire and then send it north.

Jelaudin smiled down at the crowd who had gathered that night, knowing they would leave with him to the next town and the next. He would arrive at Kabul as the spiritual leader of an army and he thought that city would swell his numbers more than anything he had seen. Perhaps the hand of God truly guided him in this, he did not know. He was a poor vessel for Allah, but how else did God work if not through the hands of men? Perhaps he was the instrument of vengeance. Allah was truly good to give him a second chance.

The Mongol tumans rode hundreds of miles in all directions, an explosion of men and horses that attacked every place where there were people to make afraid. The word of their quest spread almost as fast and rumours of great treasures in return for information seemed to have wings. By the tenth day, Jebe found a man who said he knew the mountains where the Assassins had their base. Jelme found two more who claimed to be related to a family serving them in their fortress. In each case, the destruction of their cities stopped on the instant and that brought even more to talk to the Mongol generals, desperate to save themselves. Twice Mongol scouts returned from a fruitless ride, with no sign of a city of Assassins. The men who had misled them were fools or liars, but they were killed and the tumans moved on.

Chagatai had ridden north with Tsubodai, almost in the track the general had ridden to hunt the shah. In the foothills of steep mountains, they found a village and burned it to the ground, then moved on to another. There they were met by a group of senior men pleading for a private audience. Tsubodai arranged it and, when he heard what they had to say, one of the men did not return to his home. Instead, he travelled with the Mongol general, riding as fast as possible back to Genghis. By the time they reached the khan, three others were there to claim the gold, each with a different location for the Assassins.

Genghis greeted Tsubodai as he rode in, his expression weary.

‘Another one, Tsubodai?’

The general’s excitement dropped away.

‘There are more?’ he said.

Genghis nodded.

‘Either they are thieves who believe I will give carts of gold for lies, or the Assassins have whispered different locations in a dozen places. If they are as ancient as your Yusuf claims, I think it is the last.’

‘I have one man who claims to know, lord. I do not think he is a fool or a thief like the rest.’

Genghis raised his eyebrows, knowing Tsubodai’s judgement was sound.

‘Bring him to my ger when he has been searched for weapons,’ he replied.

Tsubodai brought Yusuf to interpret, still dusty from the long ride back to the camp. The village elder was painfully nervous as he faced the khan. Sweat poured off him and he smelled strongly of excrement and garlic in that small space. Genghis breathed shallowly as he came close.

‘Well? You told my general you knew something,’ he snapped, tired of the men who had come with gold in their eyes. He waited impatiently as Yusuf turned his words into gibberish and the stranger nodded, already terrified. Three dead men lay in a shallow pit outside. Genghis had made sure this one saw their upturned faces as he passed into the khan’s ger. It explained the sour smell that hung around him like a mist.