But the Macedonians’ trumpet peals followed only a heartbeat later. Soldiers rushed to their positions. There were brisk commands in the Macedonians’ harsh dialect: Form up, hold your position, hold the line! The Macedonian infantry, eight deep, made a wall of hardened leather and iron.

Alexander had, of course, been prepared. Anticipating this assault, he had let his foe approach as close as he dared. Now was the time to spring his trap.

Abdikadir took his place, three ranks back from the front. To either side were nervous Tommies. Catching their glances, Abdikadir forced a smile and raised his Kalashnikov.

He got his first good look at a Mongol warrior through a gun sight.

The Mongols’ heavy cavalry was at the center of the charge, with the light cavalry following behind. They wore body armor made of strips of buffalo leather, and metal helmets with leather guards over their necks and ears. Each man was loaded with weapons: two bows, three quivers, a lance with a vicious-looking hook on the end, an axe, a curved saber. Even the horses were armored, with broad leather sheets that guarded their sides, and metal caps on their heads. The Mongols, carapaced, bristling with weapons, looked more insectile than human.

But they weren’t having it all their own way. At a trumpet peal, archers popped up over the parapets of the walls of Babylon, and arrows hissed through the air, over Abdikadir’s head, thudding into the advancing Mongols. When a rider fell there would be a tangle, briefly disrupting the charge.

Now more arrows fell, ablaze, their tips dipped in pitch. They were aimed at flame pits, bales of hay soaked in pitch in the ground. Soon great pockets of flame and smoke were bursting up beneath the Mongols. Men screamed, and their horses shied and refused. But, though the grit of casualties slowed the Mongol advance, it did not halt it.

And once again the Mongol heavy cavalry slammed into the Macedonians.

All along the line the Macedonians fell back. The momentum of the Mongols’ charge, and the sheer ferocity with which the horsemen wielded their swords and maces, made that inevitable.

Abdikadir, now only a meter or so from the worst of the fighting, saw rearing horses, flat Mongol faces looming above the struggling crowd, men fighting and dying. He could smell blood, dust, the sweat of terrified horses—and, even now, a rank, buttery stink that could only be the Mongols themselves. The sheer density of men and animals, the roar of ten thousand voices, made it difficult to fight, even to raise a weapon. As blades hissed in the air, blood and body parts flew in scenes of almost absurd, impossible carnage, and gradually the screams of rage turned to howls of pain. More pressure came when the Mongol light cavalry followed up their heavy counterparts, pressing forward where the heavy cavalry had made room, jabbing with their swords and javelins.

But Alexander struck back. Brave infantrymen rushed from the back of the Macedonian line carrying long hooked lances; if the lance missed, the hook could dismount a warrior. Mongols fell, but the Macedonian infantrymen were cut down like flowers before a scythe.

Now, through the clamor, a Macedonian trumpet sounded a clear peal.

At the center of the field, just before Abdikadir, the surviving Macedonian front ranks pulled back, melting through the ranks behind them, leaving their wounded and dead. Suddenly there was nothing left, nothing between Abdikadir and the most ferocious horseback warriors who had ever lived.

The Mongols, startled, their horses shying, hesitated for a second. One immense man, short but wide like a bear, stared into Abdikadir’s eyes and raised a stubby mace that was already dripping with blood.

Captain Grove was at Abdikadir’s side. “Fire at will!”

Abdikadir raised his Kalashnikov and pulled the trigger. The Mongol’s head exploded into a mist of blood and bone, his metal cap hurled absurdly into the air. His horse bolted, the headless body sliding from the saddle into the pressing crowd.

All around Abdikadir the British fired into the mass of Mongols, antique British Martini-Henrys and Sniders making precise coughs against the clatter of the Kalashnikovs. Men and horses disintegrated before the withering hail of bullets. Grenades flew. Most of them were just flashbangs, but that was enough to terrify the horses and at least some of the warriors. But one exploded under a horse. The animal seemed to burst, and its rider, screaming, was hurled away.

One grenade landed too close to Abdikadir. The blast was like a punch to the stomach. He fell backward, his ears ringing, his nose and mouth filled with the sour, metal taste of blood, and the chemical tang of the ignition. He felt somehow dislocated, as if he had been knocked through another Discontinuity. But if he was down, a corner of his mind told him, there was a hole in the line before him. He raised his rifle, fired without looking, and struggled to his feet.

The order came to advance. The line of British strode forward, firing continually.

Abdikadir moved ahead with them, snapping a new magazine into his weapon as he did so. There was no open ground; he had to climb over earth littered by corpses and body parts, in places slippery with entrails. He even had to step onto the back of a wounded man, who screamed in agony, but there was no other way.

It was working, he thought at first. To left and right, as far as he could see, where they were not dying in their saddles, the Mongols were falling back, their weapons unable to match the firearms of six hundred years and more after their time.

But now Abdikadir heard a high-pitched voice— a woman’s voice—and some of the Mongols clambered off their horses. They actually advanced toward the gunfire, using the bodies of their comrades and their horses as cover. Abdikadir recognized the tactics—scan for threats, move, take cover, scan again. They were using their bows, the only weapon they had that could match the guns’ range, and took turns to cover each other as they made their way forward: a maneuver called pepperpotting. And as they fired, Macedonian screams and a torrent of fluent Geordie oaths told Abdikadir that some arrows were striking home.

These Mongols had been trained to withstand gunfire, he realized. Sable —it had to be, just as they had feared. His heart sank. He snapped in another magazine, and fired again.

But the Mongols were closing. Abdikadir and the other riflemen had been assigned a shield bearer each, but these were being brushed aside. One horseback rider almost got through to Abdi, and he had to swing the rifle, using the butt as a club. He got a lucky hit on the man’s temple, and the Mongol reeled back. Before he could recover Abdikadir had shot him dead, and was looking for the next target.

From his elevated position on the Ishtar Gate Josh could see the great sweep of the battle. Its bloody core was still the slab of struggling men and animals, directly before the gate, where the Mongol heavy cavalry had collided with Alexander’s Foot Companions. The Eyes were everywhere, like floating pearls above the heads of the struggling warriors.

The heavy cavalry was the Mongols’ most powerful instrument, designed to smash the enemy’s strongest forces in a single blow. It had been hoped that a sudden assault with gunfire would do enough damage to the heavy cavalry to blunt that blow. But for whatever reason the Mongols had not fallen back as had been hoped, and the armed troops were getting bogged down.

This was bad news. There had only been three hundred British troops in Jamrud, after all. Their numbers were no match for the Mongols, and even if every single bullet took a Mongol life, Genghis’s troops would surely overwhelm them at last, through sheer numbers.

And now the Mongols threw more cavalry around the wings of the battlefield to envelop the enemy. This was again expected—it was a classic Mongol maneuver called the tulughma— but its sheer ferocity, as the new units smashed into the Macedonians’ flanks, was staggering.