‘Lady,’ he said, for she had fallen silent and he felt that he ought to say something, but he struggled for words and it was a while before he tried again. ‘Lady, I am glad to find you safe.’

‘It seems that once again I owe you my thanks.’ She did not smile, and he struggled to understand her mood. She had not fled, like the nymphs from Pan, or grown angry and chased him to his doom like Diana, but she still seemed a distant vision, almost as if she was a dream in his waking mind. His jerkin was off, and the tunic came away far more easily. He sat on one of the wooden stools beside the wall to remove his boots and socks. Sulpicia Lepidina watched him, eyes unblinking. ‘I am grateful.’

‘Longinus did more,’ he said, emphasising the name.

‘Ah, Longinus.’ She gave the same weight to the word and smiled to show that she knew his secret. ‘He is a remarkable man. All of the Batavians would willingly die for him – even my husband, I think, and he is not usually a man to sacrifice for others. He tells me it is a great compliment that I was told. The clearest sign that the cohort accepted me.’ She sounded puzzled by this glimpse into a strange and foreign world. ‘But in truth he knew my family, and there are favours and friendship from long ago.’

Ferox thought once again how often that was true, and prominent people knew each other or found mutual friends even in the far corners of the empire. He also thought that his feet were the foulest things he had ever seen and felt even more ashamed and unimportant. She was like a statue come to golden life, even if her fair hair looked dark and slick from the water.

He stood up, still with his trousers on.

‘If you think you are bringing those filthy things in here then you are much mistaken, Flavius Ferox.’ The mockery was gentle, even if the tone was firm. ‘This is the best bath I have had since I arrived here, and since I cannot in decency visit a whorehouse I intend to make the most of it.’

‘Shall I go?’

She tilted her head slightly to one side. ‘Are you truly such a fool?’

He met her eyes, and began to undo his belt. ‘I think I am dreaming a hopeless dream,’ he said, ‘and fear that any wrong step will make me wake.’

‘I told you, this a night when laws and rules do not hold sway.’ She pushed herself back into the main pool and swam towards him. Her eyes looked bright and he could not tell whether it was fear or excitement.

With his clothes gone he rushed forward and dived in, sending water flying and making her shriek.