‘Should we fear you?’ Lucius demanded.

Aulus sucked in his breath and his whole frame shook. Lucius might not suppose that this priestess could strike them dead on the spot, but he did; the bones that littered the space between them made him believe that others had suffered such a fate.

‘You should fear what I may say, Falerii.’

‘If you, Sybil, can see my future, then it is already decided. What need then have I to fear it?’

A finger was used to summon a hunched, unidentifiable figure, who knelt before the Sybil holding a framed papyrus. She, with no more than that index fingernail, executed a series of strokes. The light from the torches behind her framed the thin material, so both boys saw, as silhouettes, those strokes translated into some kind of drawing, this as she hissed her prophecy.

‘One shall tame a mighty foe, the other strike to save Rome’s fame, neither will achieve their aim. Look aloft if you dare, though what you fear cannot fly, both will face it before you die.’

A sweep of the hand detached the papyrus from its flimsy frame, causing it to roll itself like a scroll, which the Sibyl took and threw at their feet. Lucius bent to pick it up, opening it to reveal a drawing of a bird in blood red, crude, but clearly an eagle with wings outstretched in flight.

‘What does this mean?’ demanded Lucius.

The laugh was high and humourless, a cackle that echoed off the walls. ‘You are clever, Falerii, you decide.’

Lucius might be impious, but what happened next dented even his studied pose. He let out a strangled cry as the papyrus began to smoke in his hand and the hole of a burn appeared in the centre, spreading rapidly, a brown-edged nemesis consuming the document, but not before that crude red drawing was burnt with equal force into their minds. Just as it singed Lucius’s hand, forcing him to throw it to the ground, all the torches in the cave went out, plunging them into darkness. Aulus began to howl incantations to Jove, the greatest of the gods, seeking protection for both himself and a friend now clutching his arm in a painful grip. The lantern-light that appeared behind them offered a salvation that both boys took with alacrity and they stumbled out of the cave of the Alban Sybil, following a light that they could never catch.