The boy leaned forward to expose the grid of letters he had borne all his life but never seen:

PEEO
NERR
OSRI
ACTA

Cornelius, bending stiffly, inspected the boy. ‘Tell me again where this thing came from, Thalius?’

Thalius shrugged. ‘I have only legends, passed down for generations. The original Prophecy was a poem, sixteen lines long. It was burned at Hadrian’s orders. But it contained an acrostic - the first letter of each line, perhaps making up the core of the Prophecy’s message - that was remembered and passed on. And then, at some later time, it was encoded into this grid form.’

‘Then this mass of scars is all that is left of your famous Prophecy.’ Cornelius peered, pointing to the letters with his finger. ‘Well, if it’s an acrostic it’s cleverer than the one on your wall, Thalius. That one made sense whether you read it up or down, back or forth. This one doesn’t make sense any which way!’

‘But I think it does,’ Aurelia said. Tension shaped her aged, vulpine face, and Thalius wondered how he could ever have found her attractive. She said, ‘It is how I visualised it, but now I can see it - here, see the A and O in the lower left, upper right corners. Alpha and omega - remember? This is an acrostic compiled by and for Christians, just like the Pater Noster.’

But how could that be? Thalius wondered, chilled. For if the old legends were correct the acrostic came from a poem written down in the year of the birth of Christ, when there were no Christians.

Cornelius said, ‘But there is another A, another O—never mind! Can you decipher this jumble?’

‘With the start and end points of the A and O, I think I can, yes.’

‘Then do it, woman!’

Aurelia paused, staring at the scar for a long breath. Suddenly, quite uncharacteristically, she seemed hesitant. ‘First we must be sure we want to know.’ She turned away from the boy. ‘You Romans have a word for such a moment as this, Cornelius: discrimen, a crucial, life-shaping decision, a choice that might lead to triumph or catastrophe. Even if I can read the Prophecy, should we follow its advice? Constantine’s elevation may be the most significant event ever to have occurred in Britannia. Rome is the world’s greatest power, and decisions made by emperors cause history to shudder. And now we propose to deflect an emperor from his mighty path. History’s Weaver may want this, but do we? Are we sure? Cornelius?’

Cornelius considered. ‘If left unchecked this emperor will dissipate the very strengths that have made Rome strong. Rome must rediscover itself - and if Constantine is the man to lead that revival I will be happy. But he must be shown the way. And you, madam?’