The surviving twin, Virtus, was also in trouble, potentially. Despite his insistence that he kept aloof from his brothers’ activities, Justinus had remembered something: ‘When we picked him up at their shack in the marshes, I noticed his wife, Byrta, was wearing a good quality scarf in a dark red material. Silvius, if you can ever find any of the runaway slaves who belonged to Modestus and Primilla, you must show them that scarf. Primilla was wearing something like it when she left home.’

Piece by piece, we were linking the Claudii to their victims. We also had the unusual chain that Nobilis must have given to Demetria; I was confident that belonged with the cameo taken from the Rome courier on the Via Triumphalis. Petro would send the cameo for comparison; Silvius would take it to the Dioscurides workshop for absolute confirmation.

We asked both Probus and Virtus about their connection with Anacrites. Both blanked us. In my view, now Nobilis was dead, they were afraid they would bear the full burden as public scapegoats, but they believed the spy would extricate them. I thought they were wrong. ‘No; he will distance himself now. I know him. He will sacrifice the Claudii to save his own career.’

‘I thought they could put pressure on him?’ said Silvius.

‘We still don’t know what—though Justinus and I have a theory we intend to check. I suggest you process Probus and Virtus here in Antium. Do it fast, Silvius. But if you can, please give me a couple of days, before you send word to Rome about Nobilis.’

‘What’s the plan, Falco? I can see you have one.’

‘Let me keep it to myself. Silvius, you don’t want to know.’

Silvius and the Urbans stayed in Latium to process the survivors’ trial. I and mine set off for home. Lentullus was bringing Nero and the ox-cart for Petronius, which meant the usual maddening slow progress. It took us a day to reach Bovillae. Next morning, Justinus and I left Lentullus to drive in without us, while we rode on ahead up the Via Appia.

We passed through the necropolis where the corpse of Modestus had been found. After that came the Appian Gate, then a long straight run through garden suburbs until we hit the dark shade of two leaky aqueducts at the Capena Gate. I excused myself, and left Quintus to pass on greetings to his parents and his wife. We arranged that he and his brother would come to my house the next day, for a catch-up meeting.

I moved on, reached the southern end of the Circus Maximus, where I veered left. Since I had a mule to do the hard work, I pressed him up the hill. He carried me uncomplainingly to the crest of the Aventine, with its snooty ancient temples on the high crags, around which beetled the vibrant plebs of this place where I was born.