As I rode through Rome in the thin air of a very early morning, on my way to collect Justinus at the Capena Gate, I thought about those words. How many people have said them as a talisman, but never saw their precious love again? I wondered if Livia Primilla, the elderly wife of Julius Modestus, had spoken the words when her husband rode to challenge the Claudii. If I failed to return from this journey, Helena Justina would come after me too. I should have told her not to do it, not without an army. But that would have meant planting the suggestion that her brother and I might be in serious danger.

At the Capena Gate, Aelianus emerged to wave us off. He was mildly jealous, though as an assistant he always enjoyed being left in charge. I mentioned what had happened to Albia. ‘Aulus, it’s not your affair. Obviously this is awkward for you, but could you check with Helena that everything is all right? Will you tell her I had a thought as I came through the Forum: if she goes to see the spy, take my mother.’

‘Will he listen to your mother?’

‘Mediation! Helena will know—in a crisis with an enemy, it’s a fine Roman tradition to send in an elderly woman, with a long black veil and a very stern lecture.’

Justinus suggested leaving behind Lentullus, who could bring us news later.

So Justinus and I, taking a handful of slaves as back-up, rode off once more to Latium. Thirty miles later, as near we could get discreetly, we camped overnight, not showing ourselves at any inns where landlords might give advance warning of our presence. We planned the traditional dawn raid.

At first light, with the promise of an unpleasantly hot late August day, we reached the end of the track. Here, we knew, three of the Claudius brothers lived when it suited them, in poverty and filth, with two skinny, subdued wives and innumerable wild children. We had already passed the shack where their brother Probus mouldered; we saw no sign of him, nor his ferocious dog, Fangs.

The woodlands were sultry. Fetid steam rose from depleted pools as the marshes dried out through the summer. It must have rained recently; there was a dank, unpleasant smell everywhere. Clouds of flies rose up from tangles of half-decayed undergrowth, skirling in our faces in predatory black curtains as we disturbed them. The insects were worse than we remembered, the going more difficult, the isolation drearier.