My man Decimus Camillus Verus believed anyone opposing Vespasian must wait until Titus came home from Judaea. Vespasian himself had been quelling a Jewish rebellion when he scrambled into power. He returned to Rome as Emperor, leaving Titus to complete that popular job with his usual panache. Edging out Vespasian would merely allow his brilliant elder son to inherit the Empire early. His younger son Domitian was a lightweight, but Vespasian and Titus must be swept off their perch together or any conspiracy against them was destined to fail. This meant I had just as long to solve the mystery as it took Titus to capture Jerusalem—though from what Festus had told me before he threw away his life at Bethel, Titus would rattle through Jerusalem in two shakes of a centaur’s tail. (Titus had commanded the Fifteenth Legion, in which my brother served.)

So there we were. Anyone with the rank and the clout who fancied his own chance as Emperor could be trying to batter the new dynasty out of its olive tree. There were six hundred men in the senate. It could be any one of them.

I did not believe it was Camillus Verus. Was that because I knew him? As my client, the poor duffer seemed more human than the rest (though I had been caught like that before). Even if he was sound, that left five hundred and ninety-nine.

It was someone who knew Britain. Or knew someone else who did. A quarter of a century had passed since Rome invaded the province (and incidentally first made Vespasian’s name). Since then countless brave souls had tramped north for their tour of duty, many of them men with shiny reputations who might be feeling ambitious now. Titus himself had been typical. I remembered him there, the young military tribune who commanded the reinforcements brought over from the Rhine to reconstruct the province after the Revolt. Britain provided a social fitness test. No one liked the place, but no good Roman family nowadays was without a son or a nephew who had done his chilly stint in the bogs at the back of the world. I could be looking for any one of them.

It could be someone who had served in northern Gaul.

It could be someone in the British Channel fleet.

It could be anybody who owned any kind of ship. One of the merchants who ferried British grain to the military bases on the Rhine. An importer of hides or hunting dogs into Italy. An exporter of pottery and wine. Or, knowing merchants, a whole sticky consortium.

It could be the British provincial governor.

It could be his wife.