Since that fateful and last visit to Britain all those years ago, Constantine had pressed ahead steadily with his programme of converting his empire to Christ. He had played a long and patient game, but as the power of pagans in the ruling classes and the army had steadily diminished, he had at last felt able to proclaim Christianity as the empire’s prime religion - and to command a reformation. The wealth of the pagan temples was turned over to the Church, and the imperial treasury.

Audax rubbed a clean-shaven chin. ‘I was involved in some of that. As money-making schemes go that was a good one, even for an emperor who always had a nose for cash like a dog for a bone.’

Thalius laughed, but winced at the pain. ‘That’s cynical for a soldier of the Emperor’s bodyguard!’

Audax shrugged. ‘You can be realistic and loyal at the same time, can’t you?’

‘True. As was Tarcho, always.’

‘I’m not surprised the Temple of Claudius has survived. Even Constantine could hardly order the stripping of shrines to his own deified predecessors - especially as he is to be made a god himself.’

Thalius gaped. ‘You’re joking! After a lifetime of promulgating Christianity? Well, it will be a popular move here. They always loved Constantine in Camulodunum. Soldiers’ town, you know. And that mother of his - they are thinking of adopting her as a patron saint!’

‘Well, I know one thing for sure. Tarcho was a good Christian, of his kind. And he would never wish to be buried here.’

‘No indeed,’ Thalius said. ‘Come, let’s visit him.’

They crossed the temple floor, threaded their way down the steps through the crowded market stalls, and made their way along the city’s principal street. Once an axis of the invaders’ fort of Claudian times, it was rubbish-strewn, its gutters clogged with dirt.

And as they walked, they spoke of the aftermath of the night of Aurelia’s attempted assassination of the Emperor, the night that had entwined their fates for ever.

Constantine himself survived. His Greek doctor said that though his wound was deep, the narrow blade had fortuitously missed any major organs. Aurelia herself, who had hidden her fanaticism from Thalius until the moment of the attack, was cut down immediately by the blades of the Emperor’s guards, and that was the end of her. Tarcho shielded Thalius and Audax from the guards, but they had all been taken into custody as the search for complicity began. The worthy missive Thalius had haplessly carried might have been enough, in the fevered atmosphere of a paranoid court, to see him executed. Thalius always believed it was Tarcho himself who saved him, by arguing forcefully with his military accusers for Thalius’s naiveté and innocence - not to put too fine a point on it, his stupidity.