An Alan cut down at Ballista from the left. The northerner took the blow on his shield, without looking thrust his sword around the side of it, felt the steel tip catch, kicked on. A nomad in front was yanking his horse around to flee. Ballista smashed the edge of his blade backhanded down into the man’s left shoulder. The pony took off. The nomad toppled into the stony bed of the river. The stones ran red.

Ballista reined in, checked all around for threats. There were none. Probably half the Alani were down – loose ponies bolting everywhere – the rest were scattered in all directions, hunched low over the necks of their mounts, pushing hard for their individual safety.

‘Rally on me,’ Ballista bawled, first in Persian, then in Greek. His voice had been trained over the years to carry across a battlefield. ‘Form one wedge.’

The Sassanid clibanarii were good warriors. None spurred off in mindless pursuit. Within moments, they were jingling into formation. The thirty or so Suani were slower, some had to canter back from the beginnings of a chase. But soon they began to fall in behind.

Ballista looked back towards the village. A ragged column of Suani warriors on foot was jogging out. Castricius had them in hand.

‘At the trot, advance.’

Almost at once they rode into the wall of fog. The world was reduced to a few yards of shifting greyness. Sounds – the snort of a horse, the clink of metal touching metal – were muted. The air smelt of mist, water, wet stone and damp horse. It was like riding into the demesne of some bleak underworld.

Ballista glanced over each shoulder. Rutilus on one side, Maximus the other; serried ranks of Sassanids behind. The fog pearled on beards and cloaks. The damned croaking of frogs started up – brekeke-kek, ko-ax, ko-ax. From further away came an indistinct roaring, like surf on a rocky shore.

Ballista flinched. With a whir of wings, a flock of white doves dived out of the mist. They wheeled just over the column, and were gone. Shouts, curses from the rear. Ballista turned to the Persian officer tucked in behind him. ‘Pass the word for silence.’

‘Those birds are unclean. Like lepers, they must be driven out,’ the Persian said.

‘Surprise is our only hope. We must not let them know we are coming.’

The order to be quiet hissed back through the ranks.

The roaring was getting louder, sharp sounds within it becoming distinct.

‘Not far now,’ Ballista muttered.

Rutilus leant forward, whispered near Ballista’s ear, ‘Hamazasp can take us in the rear.’

Ballista actually laughed. ‘Allfather, I hope not.’ He stopped laughing. ‘It depends how active is his treachery; how brave he feels. I think he will wait and see who wins.’

A black, moving mass appeared ahead through the vapour; not above fifty yards. The clash of weapons, yells, and screams of men and horses. Ballista flung up his hand. They halted, automatically dressed their ranks. Ballista turned in the saddle. ‘We are there,’ he said softly. ‘They are still fighting. We are in time. Now – on my word, ride hard, but keep closed up, stop for nothing. Our infantry will be here to add their weight soon.’

‘Now!’

They moved off at a walk and went straight up to a close-in-hand canter. The noise of fighting swelled.

Even the Alani at the very rear did not see or hear them coming. The nomads were too noisily intent on the trapped Sassanid warriors in a tight-wedged knot beneath the lilac standard. The Alani were circling, pouring arrows in from all sides, from every trajectory.

The first of the Alani Ballista killed literally never knew what hit him. He had just released an arrow, was reaching for another, when Ballista’s sword caved in the back of his skull. Ballista neatly retrieved his weapon. The next man looked around, an arrow notched in his bowstring. Ballista’s heavy blade smashed bow, arrow, hands to ruin. The Nisean stallion barrelled a pony aside. Ballista forged on. Behind him welled up a chant of ‘ Peroz, Peroz.’ In front rose cries of fright.

A warrior with a shaggy sheepskin cap sliced at Ballista. Long training let the northerner watch the blade, take it on his own, roll his wrist to force it wide, and repost; all one fluid movement. The nomad jerked back. Not far enough – the steel sliced across his face. The blood sprayed into Ballista’s eyes; hot, stinging. Half blinded, Ballista finished the man with two chopping blows.

Ballista kicked on. He wiped his eyes, and his Nisean went down. He used a horn of the saddle to push himself off, throwing himself away from his falling horse. The ground rushed up. He landed awkwardly. His helmet rang on a stone. The great weight of the stallion crashed beside him.

Ballista tried to get up. Stay on the ground, and he would die. Sharp hooves were stamping all around. A wave of nausea engulfed him. His legs gave way. Curling up tight, his arms covering his head, the blackness overtook him.

Ballista did not know how long he had been unconscious – he was still in the same position – probably but moments. Legs straddled him. He groped for his sword. It was gone: the wrist loop must have snapped. He looked up. His eyes were gummed with blood; he did not know if it was his own. Maximus and Rutilus, back to back, stood over him. Suani warriors on foot ran past. They were cheering, laughing with the courage that comes from spearing fleeing enemies in the back.

‘This time it is over,’ Rutilus said. ‘They are broken.’

Ballista was helped to his feet by Maximus. As if from a great distance, he heard ‘ Peroz, Peroz.’ He drew a deep breath, made to give orders to keep some men together in case Hamazasp tried anything. The nausea rushed up to his throat, his mouth – a cloying, oily taste of burnt almonds. He got back on his hands and knees, and painfully started to throw up.

Peroz! Peroz!

XXXII

Prince Narseh and Azo, the man who would be king of Suania, were regarding the Caspian Gates. It was a desolate sight. Ballista’s reconstruction had not been completed before the Alani arrived. During their siege of Cumania, the nomads had removed and burnt all the woodwork from the Gates. They had even begun to demolish the stone gate across the track at the eastern end.

Yet, despite their ruinous state, the Caspian Gates had been a choke point in the rout of the nomads. The path down which Ballista rode towards the royal entourage had been mainly cleared of the dead, but they were everywhere else. Sassanid work parties were busy. They were gathering their own dead, treating them with respect, getting them ready for exposure to the birds of the air, as was the Zoroastrian way. Things were different with the corpses of the Alani and those Suani who had fallen supporting Saurmag. Stripped naked, sometimes mutilated, they were unceremoniously being thrown into piles out in the valley. It was the natural order, Ballista thought, for some things to be stacked: sheaves of wheat, amphorae, barrels. Corpses were not in that category. The pallid, blue-white tangles of limbs were grotesque. They said something deeply troubling about the inhumanity of mankind.

Ballista climbed down from the saddle, passed Maximus the reins. Narseh and Azo turned to him. Ballista bowed to each, blew them a kiss. If he had performed full proskynesis, he was not sure he could have got up again unaided. He was still dizzy; the taste of bile and burnt almonds remained strong in his gorge.

‘Ballista, Framadar.’ Narseh stepped forward. He was smiling, but his dark eyes were melancholy. ‘Nasu, the very daemon of death.’ He embraced the northerner; kissed him on each cheek, the eyes, the lips. His blue-black beard rasped across Ballista’s face. ‘I am in your debt. Your intervention turned the battle. It broke the Alani. Maybe, in the mist, they thought the numbers with you larger. We will never know.’ The prince stepped back, studied Ballista. ‘I was told you took a bad fall. Are you hurt?’

‘I will live.’ Ballista smiled. ‘But, I am afraid, I cannot return the charger Gondofarr lent to me.’

‘Gondofarr is dead.’

‘I am sorry.’

‘Tir-mihr is badly wounded. Our losses are heavy.’

‘How badly wounded?’

‘He has been carried to the village. It will be as Mazda decrees. The mobad will send word.’

‘Hamazasp betrayed us.’

Narseh rubbed his eyes; the gesture of a tired man. ‘His Iberians fought well. His man Ztathius was killed.’

‘He sacrificed them. He was not ill. He was waiting to see who won.’

‘There is no proof.’

‘When the Alani sprung the ambush, the Iberians in the village were not surprised. Hamazasp must have been forewarned.’

‘He has sent his congratulations. We must leave things as they are.’ Narseh lapsed into silence.

Azo took Ballista into his arms, kissed him. The Suani prince was laughing. Unlike Narseh, the death of his men did not seem heavy on him. ‘I am doubly in your debt. Both for today and for when my snake of a brother and his barbaric allies rode up the pass. Saurmag would have taken me, if your men had not welcomed me into Cumania. Although “welcome” might not be quite the right word. Fifty-one days is a long time confined with your man Calgacus. Does he ever stop moaning? And the Greek called Hippothous – he has a most disconcerting habit of staring at one.’

‘They are the companions the gods have given me.’

‘If I were you, I would worship at new shrines.’

‘What happened to Saurmag?’

A cloud of anger passed over Azo’s face. ‘He escaped north to the steppe. I saw him pass. From the battlements, my arrow killed one of the traitors who rode at his side.’ The Suanian brightened. ‘A temporary reprieve. I will close the passes next spring. With his subjects unable to cross south for the summer pasture and unable to trade for iron and salt, a suitable gift should induce the chief of the Alani to hand Saurmag over.’