At street level, I saw Myrinus so warned him that if he or Secundus saw Cosmus they should only approach him with caution. I had to explain why. Myrinus told me that at one point Secundus taught Cosmus wrestling, but he gave up. The boy was strong, but he had the wrong temperament. Secundus said he wasn’t suitable to train in combative sport, he grew too angry.

Strong and angry. That fitted.

I found Dromo.

‘I packed all the stuff like you ordered me. My master’s belongings that he lent you are all on our handcart, but yours won’t fit.’ My modest luggage was bundled up neatly enough, but lay apart in the atrium, quarantined. If the commission was over, in Dromo’s eyes I ceased to have rights.

‘Either mine goes on the cart as well, Dromo, or the bad news is you will have to make two trips. Never mind that now. The good news is, you don’t have to do it straightaway because I need you to come with me to see the vigiles.’

Dromo kicked the handcart. ‘Well, that’s a waste of my time! I didn’t need to do all that.’

Working with me had failed to teach him any grasp of logic.

At the Second Cohort’s station house, Titianus was about to go off duty. I made him stay to take down details, emphasising that this was not simply a runaway slave, but one who had committed three murders of citizens. Titianus put his head out into the colonnade and shouted a few orders, though I could hear little sound of response.

‘You seem to have cleared up the Aviola case!’ Titianus groused, making no effort to hide his jealousy. ‘So now you want me to do the tiresome bit, put myself out catching him.’

I stayed calm. ‘If you can make the arrest, Titianus, you are welcome to the glory. The whole Esquiline community will be delighted the vigiles have acted with such efficiency. Besides, don’t you have a particular remit to track down runaway slaves?’

Titianus softened up. ‘That’s because we run into so many of the buggers while we’re doing our rounds. The Second funds its entire Saturnalia drinks budget from the rewards we receive for returning lost slaves to their masters. Last year, one good-looking Syrian acrobat from a senator’s entertainment troop covered all our bites for our big do.’

‘Very public-spirited. Do you splurge all your perks on entertainment?’

‘Officially any thank-yous have to be put towards equipment. We can run with that as well. Any time we need new fire mats, we shake out a few homeless varmints from under bridges, make them squeal about who they belong to, march them home and invoice for our finders’ fee.’

‘Well, just make sure you catch this raging boy Cosmus.’