In view of the weather, I did wonder why he was so heavily muffled; sometimes it seems as if everyone in Rome is sneaking up back alleys on some business that is best done in disguise.

I said I would lock up.

'We'll be off then!' Frontinus was taking his lads for a well-earned drink. He did not invite me to join them-and I was not surprised.

'Thanks for your help. I'll be seeing you, Julius-'

'Not if I see you first!'

Once they had gone I stood for a moment with a heavy heart. Now I was alone I had more time to notice things. In the yard my eye fell on an interesting stack which was buttressing the outer wall beneath a discreet covering of old hides. As an auctioneer's son I could never ignore any abandoned commodity which might be saleable; I strolled across.

Under the hides were a couple of sprightly spiders and numerous ingots of lead. The spiders were strangers but the ingots were old friends; the conspirators had intended using stolen silver to bribe their way into power. All the bars containing precious metal had been recovered by the Praetorians and carried off to the Temple of Saturn, but the thieves who smuggled the bullion out of the British mines had cheerfully cheated by sending the plotters large quantities of lead-useless for bribery. Evidently the lead had been left here for collection by an Imperial wagon train, all neatly stacked with military precision, each row at a perfect right angle to the one beneath. Lead lingots had some value to a man with the right contacts… I covered them up again, as an honest state servant should.

•

I left the gates open while I returned on my own to the manhole over the Great Sewer. Of all the foul corpses of failed entrepreneurs that must be littering Rome, this was the last I would have chosen to treat with such disrespect.