Hortensius clicked his fingers, and his attendant handed Cicero a legal document with a heavy seal. 'Yesterday the Board of Tribunes served this writ on Rabirius.'

At the mention of his name, Rabirius looked up. 'Can I go home?' he asked plaintively.

'Later,' said Hortensius in a stern voice, and the old man bowed his head.

'A writ on Rabirius?' repeated Cicero, looking at him with bemusement. 'And what conceivable crime is he capable of?' He read the writ aloud so I could make a note of it. '“The accused is herein charged with the murder of the tribune L. Saturninus and the violation of the sacred precincts of the senate house.”' He looked up in puzzlement. 'Saturninus? It must be – what? – forty years since he was killed.'

'Thirty-six,' corrected Catulus.

'And Catulus should know,' said Isauricus, 'because he was there. As was I.'

Catulus spat out his name as if it were poison. 'Saturninus! What a rogue! Killing him wasn't a crime – it was a public service.' He gazed into the distance as if surveying some grand historical mural on the wall of a temple: The Murder of Saturninus in the Senate House. 'I see him as plainly as I see you, Cicero. A rabble-rousing tribune of the very worst kind. He murdered our candidate for consul and the senate declared him a public enemy. After that, even the plebs deserted him. But before we could lay our hands on him, he and some of his gang barricaded themselves up on the Capitol. So we blocked the water pipes! That was your idea, Vatia.'

'It was.' The old general's eyes gleamed at the memory. 'I knew how to conduct a siege, even then.'

'Of course they surrendered after a couple of days, and were lodged in the senate house till their trial. But we didn't trust them not to escape again, so we got up on the roof and tore off the tiles and pelted them. There was no hiding place. They ran to and fro squealing like rats in a ditch. By the time Saturninus stopped twitching, you could barely tell who he was.'