‘Hah!’ The laughter was abrupt. Iulus stepped forwards, a disbelieving expression quivering on his face. ‘Python is a story nurses use to scare infants and babes in arms. There is no such thing. Why should we believe you? Is this a fantastical tale, like one of my father’s?’

‘Iulus, silence!’ commanded Aeneas. ‘You’ve seen miracles. You saw the harpies, and our ships turning into nymphs.’

‘I was young. I don’t remember. They were just stories you told us to make us feel better about ourselves. Like we had a destiny! To come to this place – this wooden rubbish dump – when we used to live in the greatest city in the world!’

He rounded on the centaur. ‘And you, monster, slayer of men. There is no room for you here in Lavinium, nor in my city of Alba Longa. We follow the new rules there. There is no darkness, and there are no gods. Father – dear, pious Father – I’m going back to my people. Let me know when you’re out of your dotage. Be strong,’ he finished, sarcastically, striding out of the room, and his guard of companions followed him, curling their lips with distaste.

‘My lord,’ said Aeneas, apologising. Elissa could not help noticing the look on his face. It was as if he’d lost something infinitely precious.

The centaur cut over him with a stamp of his foreleg. Then he carefully removed the chain from around his neck.

Elissa, looking at the casket that hung from it, felt that she might be drawn into it, shrunk, absorbed wholly into its shining walls. She began to feel dizzy. Its surface was rippling with extraordinary colours, iridescent, shimmering. There were three animals engraved upon it. A lion, little more than a cub, was crouched in the right-hand corner. Facing across from it was the form of a young wolf, lips bared. And in between them, splashing upwards as if leaping out of water, was a dolphin.

As she watched, the dolphin glimmered, enticing her inwards.

She barely heard the centaur saying, ‘Aeneas. I do not know how we can defeat this thing. But know this.’ The tremor in his voice brought Elissa back. ‘When the world was young, the god Apollo laid low the great Python with an arrow forged by the smith-god himself, and took the Oracle of Delphi from him. Such a terrible weapon could not be left intact, and nor could it fall into the hands of the enemy. The arrow was split in two. Apollo placed the Arrowhead into this casket, and entrusted it to us, the centaurs of Italia.’

‘So where is the other half?’ Elissa asked, still gazing at the box, her eyes quick and bright. Silvius was at her elbow, peering over her shoulder. She could feel his hot breath on her neck.

The centaur twitched his nostrils. ‘That is only known in Achaea. Someone must find it out, and find how Python can be destroyed.’