Olenus got up, wincing as his back straightened. 'Let us go to the cave.

Take your bow and pack. You can pick up those pelts and kill the last wolf on the way home.' He walked over and grabbed the lamb tied up by the hut.

The animal bleated plaintively as the rope was fastened around both its back legs and it was dangled over Olenus' shoulder.

Tarquinius followed the haruspex along the same track they had been on a few weeks before. They climbed in silence, until only the scrubby grass beloved by sheep and goats remained to cover the stony ground. The weather was much calmer than usual on the mountain and a few clouds sat unmoving overhead.

An eagle appeared over the crest of the ridge above, bringing a smile to Tarquinius' face. It was always a good omen to see the most regal of birds.

They were still picking their way up the steep slopes by early afternoon. A cool breeze kept temperatures bearable, but in the fields far below it would be a different matter.

Olenus came to a halt, a fine covering of sweat on his wrinkled forehead.

'You're in good shape, old man.' Glad of the rest, Tarquinius took a pull from his water bag.

'Sixty years living on this mountain.' Olenus scanned the harsh environment of rocks and the occasional bush which had survived the extremes of weather. It was desolate but beautiful. The sky had emptied of clouds, the only sign of life the bird of prey drifting on thermals. 'It's been a good place to live and it will be a good place to die.'

'Please stop talking like that!'

'Better get used to it, Arun. Haruspices have lived and died here since time immemorial.'

Tarquinius quickly changed the subject. 'Where is this cave?'

'Up there.' Olenus waved his lituus at the winding path. 'Another hundred paces.'

Teacher and pupil walked the last few steps to the entrance, hidden until they had virtually fallen into it. The narrow opening was barely wide enough for two men to stand abreast.

The young Etruscan gaped. He must have been past the aperture countless times searching for sheep, but nobody would ever find it unless they knew where to look. Then he smiled. The long years of waiting were nearly over.

'Mind your head.' The haruspex paused, muttering a prayer. 'The ceiling is quite low.'

Tarquinius followed Olenus, squinting as his eyes adjusted from the light outside. It was the cave in the dream, the interior just as plain as he remembered. The only evidence of human presence was a small ring fireplace in the centre of the floor.

Olenus put down the lamb, tying the rope round a large rock. He paced deeper inside, studying the wall. About thirty paces from the entrance, he stopped. With a grunt of effort, the old man reached up into a crevice with both hands, searching.

Tarquinius watched with fascination as the soothsayer pulled out a heavy oblong object wrapped in cloth. Olenus brushed off a thick layer of dust and turned to him.

'Still here!'

'The sacred liver?'

'The first one ever made by a haruspex,' replied Olenus solemnly. 'Bring the lamb.'

He led the way outside, stopping by a slab of black basalt that Tarquinius had noticed on the way in. Olenus set down the lituus and pulled a long dagger from his belt, laying it on the edge of the flat rock.

'That is just like the altar I saw in my dream!'

'There is another one, deep inside the cave.' Olenus unwrapped the bronze liver, placing it reverently beside the knife. 'But today's divination must be performed in sunlight.'

Tarquinius peered at the smooth lump of metal, coloured green with age. It was shaped exactly like the purple organ he had seen cut from butchered cattle and sheep. Bulging more on the right, the bronze had two triangular pieces protruding from its inner aspect, like different lobes of a real liver. The uppermost surface was covered in lines, dividing it into multiple areas. Spidery, cryptic symbols had been etched on each part. Having studied diagrams of the liver over and over again, Tarquinius found he could understand the inscribed words.

'It names the gods and stellar constellations!'

'All that time studying wasn't in vain, then.' Olenus took the rope from him. 'You read the whole Disciplina Etrusca twice, so you should know most of what I'm going to do.'

Tarquinius had spent countless hours spent poring over cracked parchments that Olenus kept in his hut. He had digested dozens of volumes, constantly encouraged by the old man leaning over him, indicating relevant paragraphs with long yellow fingernails. There had been three sets of books – the first, the Libri Haruspicini, was dedicated to divination from animal organs; the second, the Libri Fulgurates, dealt with interpretation of thunder and lightning. The last, the Libri Rituales, concerned Etruscan rituals and consecrations for cities, temples and armies.

'Gently, little one,' Olenus whispered.

The lamb pulled the rope taut, an alarmed look in its dark brown eyes.

Speaking reassuringly, the haruspex placed the animal on the centre of the basalt. 'We thank you for your life, which will help us understand the future.'

Tarquinius moved closer. He had seen Olenus perform sacrifices before, but not for some months. The haruspex had never used the bronze liver alongside a fresh offering. And although Tarquinius had tried divining many times after he had been hunting, they had only been practice runs, predicting things like weather and harvest yields.

'It is time.' Olenus picked up the dagger. 'Observe how a fresh liver may be read. Hold him properly.'

Tarquinius gripped the lamb's head and extended the neck towards Olenus. With a swift slash of the blade, the old man cut its throat. Dark red venous blood gushed on to the altar in a thick stream, spattering them in droplets.

'See how it flows to the east?' Olenus cried with glee as the liquid ran away. 'The omens will be auspicious!'

Tarquinius gazed eastward, to the sea. It was from across the water, from Lydia, that the Etruscans had come many centuries ago. According to ritual, the gods most favourably disposed towards humans also dwelt in that direction. Not for the first time, he felt a strong urge to journey to the ancestral homelands of his people.

Olenus laid the dead lamb on its back, exposing the belly. With deft movements, he sliced open skin and muscle from groin to ribcage. Shiny loops of gut spilled out, glistening in the sunlight.

Olenus pointed with the dagger. 'Mark the pattern as large and small intestine emerge to sit on the stone. Both should be a healthy pinkish-grey colour, like these. If they are not, it is likely the reading will be bad when you reach the animal's liver.'

'What else can you see?'

'The wave movement in the intestines is still strong, which is good.'

Tarquinius watched the regular pulses in the small bowel, moving along digested material in a futile attempt to stay alive. 'Anything else?'

The haruspex leaned closer. 'No. When I was a boy, old men used to claim they could interpret much from the bowel and the four stomachs. They were charlatans.'

Olenus reached inside the abdomen with both hands, using his knife to free the liver from its position against the diaphragm. A few swift cuts severed the large vessels anchoring it in place. Forearms covered in blood, he withdrew the organ, balancing its rounded surface on his left hand.

'O great Tinia! Give us good omens for the future of this Arun.' He raised his eyes to the heavens, searching for the eagle that had accompanied them earlier.

'What are you doing?' asked Tarquinius.

'Reading your life in the liver, boy,' Olenus cackled. 'What better way to complete your learning?'

Tarquinius held his breath for a long time, unsure. Then, as if compelled, he found himself taking in the words. It had been too many years to hold back now, even when it was his own future being predicted.