They found a place amid the crowd gathering before the stage, and prepared to wait.

Severa pressed him, asking, ‘Do you ever think of the past, Brigonius? Of the age of Agrippina and Cunedda, of the invasion, those brief days which have shaped our lives ever since? Time heaps up remorselessly. Your northern country is restless still, but it is already sixty years since the last great revolt in the south, when the cities burned. Sixty years.’

Brigonius knew about that. His grandparents had been children then, and had survived Boudicca’s burning of Camulodunum. Until they died they had been fearful of alarms, of disorder - and of the smell of fire.

Severa said, ‘But the invasion was some twenty years before that. It is all fading away now, fading into the past. Nobody alive remembers a Britain without the Romans.’

Lepidina seemed bored. ‘Why are you going on and on about the dead past, mother?’

Severa said, ‘Because of the Prophecy. That’s why we’re here, isn’t it, Brigonius?’ She drew a leather satchel from a fold in her tunic. ‘In here,’ she said, her eyes bright, ‘is a single sheet - old-fashioned Latin, scratched onto a bit of parchment. Only sixteen lines. It’s the Prophecy, Brigonius. The Prophecy I mentioned in my letter. It was written down at the birth of Nectovelin, a cousin of my grandmother, Agrippina.’

She told him something of the history of the Prophecy: how Agrippina and Cunedda had penetrated the house of Claudius himself, how a startling bit of foretelling had come true - and how Claudius afterwards had confiscated the document and placed with the Sibylline oracles. ‘My grandmother moved to Rome, and spent many years trying to retrieve the document. She failed - and so did my mother - but at last I found the right person to bribe.’

Lepidina tutted. ‘You tell me off about breaking the law with a bit of silver at my neck and you raid the vault of the Sibylline oracles! You’re a hypocrite, Claudia Severa.’

‘But what is this Prophecy?’ Brigonius asked.

‘It is nothing less than a sketch of the future - the future of the Romans, and of Britain under them.’

‘The future?’ He tried to guess dates in his head. ‘But it must already be more than a hundred years old.’

‘A hundred and twenty-six,’ Lepidina said brightly. She fingered the fish pendant at her neck. ‘It was written down in the same year as the birth of Jesus of Judea.’

‘Who?’

Severa snapped, ‘Just the hero of another mystery cult out of the east, another fad for my daughter and other silly children in Rome.’

Brigonius grinned. ‘If the Prophecy is so old we are already in the future!’