The Emperor said, ‘Can you see the man behind me? The tall man with the spectacles - I mean the bits of glass on his nose? He is my physician - a Greek, and a very good one. He is called Philip. If you want you can let Philip take the knife from you, then I will live. Or you could choose to twist the knife and I will die.’

Audax heard Aurelia yell, ‘Kill him, slave! Kill the monster—’ Then her voice was muffled, perhaps by a soldier’s heavy hand.

Audax stayed still, his arm aching.

The Emperor said, ‘Why do you think that woman wants me dead?’

‘The words on my back say you will die.’

‘All right. But what do you think, Audax? Do you think your choice should depend on a prophecy? Look at me. What do you see?’

Audax considered the man before him: heavy-set, powerful. He reminded Audax of Tarcho. ‘A soldier,’ he said.

‘Yes. Good. That is what I am above all, and always will be.’

‘I want to be a soldier,’ Audax said.

Constantine nodded, just a little. ‘Then I promise you shall be - if you choose to let me live. But it is your choice, Audax. Quite a thing, isn’t it? Here we are, Emperor and slave, the highest and the lowest, the top and the bottom. And yet because of a simple knife, at this moment it is you who holds more power than anybody else in the world - you, at whose every tremble all history shudders.’

‘It is true,’ Thalius whispered. ‘It is true! The unravelling of a Prophecy three centuries old - the fate of the whole world to come - all of it boils down to this moment, a knife in the hand of a slave!’ But Tarcho hushed him roughly.

Constantine whispered, his voice growing weaker, his face greyer, ‘The world is a complicated place, Audax. The future is unknown. And yet we must make choices even so. What do you think such choices should be based on? Words burned into your back, or the judgement of a man like me?’

Audax felt detached from the world, as if he was going to faint. His arm, outstretched, was so stiff, his blood-soaked fingers so numb, that he could barely feel the knife any more, and he didn’t know if he was keeping still or not.

And as the world turned to grey, he thought he saw the walls of the room break down, like a collapsed wall in the mine, revealing corridors leading off to misty destinations. Dimly he discerned that the Emperor was telling the truth, and so was Thalius, that momentous events affecting the lives of people for generations unborn depended on what he did in the next few heartbeats. Who was he to trust, then - who or what?