But as Hadrian had aged his contradictory characteristics had become ever more pronounced. He had always been drawn to the east rather than the west, even though his own family had come from Iberia. In lands where he was already worshipped as a god, perhaps he began to conceive of himself as a monarch as aloof as the pharaohs had once been. Good Romans muttered that this went against the spirit of their enterprising city and its roots in the noisy democracies of Greece. And more practically, if the centre of the empire moved eastward, Brigonius mused, what would become of Britain, its most western extremity?

It had been the death of one of the Emperor’s favourites, the beautiful youth called Antinous, which many believed to have been the turning point of his reign. Antinous had drowned in the Nile, during one of Hadrian’s trips to Egypt. The death seemed to have unbalanced Hadrian. Suddenly you saw dedications to his lost Antinous appearing everywhere, in frescoes, mosaics and statues, on vases and on coins, in miniatures and in mimes. You couldn’t escape his beautiful face even here, in this soldiers’ corner of Britain.

It was said that Hadrian, always obsessed by his own death and subsequent immortality, was trying to create a god in the person of Antinous. It was ironic that, as Lepidina had said long ago, if Hadrian had only turned to the one mystery cult he had always rejected - Christianity - he might have found the theological solace that he sought, and on learning of a god made man in Jesus, he might not have needed to soothe his own pain by turning a man into a god.

But none of that justified the savagery of Hadrian’s latter years. In the east the Jews had risen again, once more challenging the very identity of the empire, and this supposedly tolerant, inclusive Emperor had put them down every bit as brutally as the conqueror Trajan. This harshness had trickled down into every corner of life - and even here, at the very edge of the empire, it was this harshness that was now to be turned on Claudia Severa.

At last Severa entered the room, and the desultory conversations died.

Sabinus rose and bowed. ‘Claudia Severa. Welcome.’

Severa was dressed plainly, in a simple turquoise robe and head scarf. Now in her late fifties she had aged well, Brigonius thought, though her hair, pulled back from her face, was a helmet of silver-grey. But her eyes were just as dead and cold as he remembered.

He was surprised when, without speaking, Severa crossed the room and came to sit beside him.

Brigonius looked into his own heart, and found that on seeing this woman for the first time in sixteen years his anger burned more fiercely than ever. ‘Why did you call me, Claudia Severa?’

She raised dyed eyebrows. ‘Why did you come?’

‘Do you imagine I am your friend?’