Ballista was half aware that Maximus was giving the party a lengthy account of breeding mules in Hibernia. It all seemed to hinge on cutting the mare’s mane and tail before taking her to the donkey – it humbled her pride; would probably work on women too. There was a small stream of water running down the Embolos. Idly, Ballista’s eyes tracked it back up the hill, past them and under the careering mule. The rivulet ran on beyond where the driver’s stick was being employed in anger. The water was coming from the left-hand side of the Sacred Way, from the Fountain of Trajan.

Twice the size of a man, Trajan soared up, his head and shoulders reaching level with the second storey of the building. He was near naked, as befitted a god. Other, smaller deities peered out at him from their columned niches. In the big pool at his feet, barbarians cowered. It was from this pool that the water was coming.

Odd, thought Ballista. The Romans were so good at hydraulic engineering. The water was starting to pour over the rim of the big basin at a prodigious rate. It was thick, brown, muddy. The mule, stamping and splashing, whinnied; a high call ending in a frightened hee-haw.

Realization came to Ballista in a rush: the fountain and the mule; before that, the snake and the caged bird; it was spring, a dead calm, no rain for days. Allfather, all the signs were there. They had to get out of here, get to a place of greater safety. The mule, sharp hooves flying, blocked the way ahead. On either side, the buildings crowded up on top of each other: a death trap. It had to be downhill. To where? The open orchestra of the theatre? No, definitely not; not with the tall, delicate stage buildings and the monuments looming above the seats. The gate into the commercial agora, the Gate of Mazaeus and Mithridates? It was a good structure, solidly built. No, of course not there – beyond it, the agora itself.

‘We are going to the agora.’ Ballista’s words cut across the prattle of Maximus. The familia stared. ‘We are going to run. Calgacus, you go in front; get people out of the way. Maximus, you carry Dernhelm. Isangrim, with me: hold my hand. Julia, you and your women, keep close. Hippothous, bring up the rear.’

Julia made as if to question all this, but stopped as the two freedmen and the secretary obeyed the instructions. In position, the men hauled up their unwieldy togas. A moment’s hesitation, and the three women more demurely rearranged their costume. High on Maximus’s shoulder, young Dernhelm was roaring with laughter.

‘Time to go.’

Bystanders gawped, reluctantly moved out of the way as the familia set off, slow at first, down the street. ‘Faster! Move faster!’ Ballista shouted. Aided by the slope, they picked up speed.

Out in front, Calgacus was yelling: Vir Ementissimus… diplomata

… shift it, you soft southerners. The fine details may have been lost on most pedestrians, but the general intention was clear. The crowd stepped to the sides, pointing, laughing, treating it like a prelude to the festivities. As he ran, Isangrim’s hand sweaty in his, Ballista thought how embarrassing this would be if he were wrong.

They pounded on; past the tomb of Arsinoe, past the Heroon of Androclos. The noise came as they reached the Gate of Hadrian: a great clattering rattle, like an empty wagon or chariot driven fast over cobbles. The bystanders looked this way and that, searching for the source of the noise. There was nothing in sight, just the big man and his familia, garments ridiculously hitched up, tearing past as if Hecate herself were after them.

As they hurtled into the square in front of the library of Celsus, the noise changed to a strange, hollow rumble, like distant thunder. The paving stones shifted. Ballista and Isangrim stumbled. Holding each other’s hand, their momentum helped keep them upright. Maximus was holding Dernhelm just ahead; Calgacus still out in front; the others behind, still on their feet. They all ran.

The noise surged, changed again – now a bull roaring in a cave. The ground punched up into their feet. Ballista lost his grip on Isangrim. Down, scrabbling on the gritty stones. People falling, screaming all around them; Ballista reaching for his son. Between the paving slabs, earth was thrown up like chaff from a winnowing sieve. The slender columns of the library of Celsus swayed. The air seemed to tremble.

Ballista and Isangrim clasped hands, clawed to their feet. They could see Maximus’s back vanishing into the gateway. High on the pediment above the Hibernian’s head, the statues of Augustus and the first imperial dynasty shifted and moved – a sinister, stiff ecstasy of primitive priests about a macabre blood ritual.

‘Come on!’ Ballista shouted.

Together, father and son ran into the shadow of the vaulting – a terrible crashing behind – on under the colonnade. And then… And then they were clear; out in the open spaces of the commercial forum. Nothing here to threaten them. Keep away from the equestrian statue of the emperor Claudius in the middle, and there was nothing but wooden stalls little higher than a man. Nothing to fear.

Calgacus and Maximus had pulled up in a clear space. They were doubled over, panting like animals, hugging Dernhelm. The little boy was wide eyed, silent. Ballista and Isangrim joined them.

Ballista kissed both his sons, and looked around. Hippothous and one of the maids had joined them. Julia? He looked around again. Where was Julia? He directed his gaze further afield. People everywhere: standing, milling, some running. No sign of her.

‘Isangrim, stay with Calgacus.’

‘No,’ shouted Maximus. ‘I will go back.’

‘No, look after the boys.’

Ballista headed back, against the gathering flow of humanity. Still no sign.

The din was deafening: shouts, screams – humans and animals – the horrible grinding as the works of man fell in ruin. But now the ground was still. For how long?

Back under the colonnade. Ballista shouldered his way under the gateway. Allfather, where was she?

A man ran blindly into Ballista. He was shrugged aside. Ballista fought through to the other side, desperately scanning the square.

There! Off to the right. Julia was kneeling by a fallen statue, and under the statue lay the maid Anthia. Dark blood pooled out.

Touching Julia’s shoulder, Ballista said something. She took no notice.

Ballista let his bunched-up toga drop. The white folds fell in the blood. He reached down to see if the girl was alive. What if she was? He could not lift the solid marble statue. He felt for a pulse. Guiltily, he was relieved she was dead.

Ballista started to straighten up. He stopped. Had his fear overcome his senses? He looked up. Another statue was poised on the very edge of the gate. He remembered another gate, another city. The great temple at Emesa, the statues turning in the air, rigid as they fell; the heavy, brittle impacts; the carnage among his men; the slicing pain in his leg. Now, the ground in Ephesus was still. For how long?

Again he bent down, felt for a sign of life.

‘She is dead. Come.’

Julia did not move. Inexplicably, she began to recite Latin verse:

‘Why, victor, celebrate?’

Ballista put his hands under her armpits.

‘This victory will destroy you.’

Ballista got his wife to her feet.

Quid, victor, gaudes? Haec te victoria perdet.

Half-carrying her, Ballista pulled Julia away.

Back in the agora, they reached the others.

Nearby, above the cacophony, came the sound of a hymn: Poseidon, Earth-holder, steadfast stabilizer; Avert your anger, Hold your hands over us.

Fools, thought Ballista: wrong reason, wrong deity. The gods had chained Loki deep in the earth, suspended the serpent above his head. Loki’s good-wife caught the venom in a bowl. But the bowl must fill, must be emptied. And then, in the dark, the poison gathered on the fangs, balled out and dropped on the Evil One’s unprotected face. Loki screamed, and hopelessly fought the chains and the rocks that secured them.

No point in praying. Nothing to be done.

II

It was dark in the agora. Well past dawn, and darkness had returned. Thick clouds of dust and smoke had rolled under the gate, billowed down past the theatre from the mountain. The sun could not break through. The choking yellow-brown fog had turned the Tetragonos agora, the commercial heart of Ephesus, the metropolis of Asia, into something from beyond the Styx.

The ground had stopped moving, but in the crowd some still staggered like sailors trying to recover their land legs. Near to Ballista, a man clutched a market stall and vomited. The tradesman made no objection; like many, he just stared blankly, overwhelmed by the enormity of what had happened. Here and there, individuals screamed incoherently or ran pointlessly, their wits unhinged. From the gloom came snatches of hymns: Poseidon, Earth-Holder…

‘ Dominus.’ It was Calgacus. ‘ Dominus, the house, the rest of the familia. We must get back.’

Ballista tried to get his thoughts in order: the house, Constans, Rebecca and Simon, the others… the horror. Of course Calgacus was fearful – Rebecca.

Hippothous drew near. His sandy hair was dusty, his blue eyes shot with red. ‘ Dominus, with an earthquake this severe, there is never just the one shock. All the subterranean wind cannot force its way out at once. Air is bound to be left in the narrow places of the earth. The ground will shake again as it escapes.’

Ballista stroked the heads of Isangrim and Dernhelm. He tried to think.

‘The boys’ – Hippothous gestured – ‘the women, they will be safer here in the open. If you go with the men, I will look after them.’