Ferox thought back to Domitian’s rage at the conspirators who had backed Saturninus, of that mottled red face ordering him to seek them out, and his soul shuddered at the memory of the trials and deaths that followed. The men he found were all guilty, all oath-breakers, but the cruelty of the emperor’s vengeance and the way it reached out to claim victims from the condemned’s families and friends haunted him. It made it hard to trust yet another Roman demanding the truth.

The provincial legate seemed to sense his doubt, and again patted him on the arm. ‘You saw that poor girl and what they did to her. Whoever helped them needs to suffer.’

The old man coughed. Ferox had almost forgotten that he was there for he had said nothing at all.

‘I have not forgotten,’ the legate said with a broad smile. ‘I do not believe you have met Quintus Ovidius. He’s a philosopher and a poet, but you must not hold that against him for he is a sensible enough fellow most of the time. He is also a very old friend of someone you know, whereas I can boast no more than acquaintance – if a very fond acquaintance, at least on my part.’

‘He asked me to give you this,’ Ovidius said, holding out his bony arm, his fingers enclosing a small leather bag. ‘There is a message as well, but he insisted that you first see this token. Even I do not know what it is.’

There was something hard in the bag, but until Ferox opened it and tipped the contents on to the palm of his hand he could not guess what it was. When he saw it he gasped out loud, regretting it immediately and yet unable to restrain himself for he had not seen the necklace for many years. It was a simple leather thong with one stone hanging from it, a rich blue apart from a thick white stripe. A friend had worn it – a friend of his youth who had died in his arms, coughing up blood after a Sarmatian had run one of their great spears right through his body.

‘The “tall tree that sways in the wind, but does not break”’ – Ovidius intoned the phrase he must have practised – ‘sends his greetings and asks that you trust his friends as you trust him. He would have written, but his eyes are weak these days.’