‘For the last three months the Nubians have been carrying out raids against our southern frontier,’ he went on. ‘Each time, they have penetrated further along the Nile, but always withdrawing before we could gather sufficient forces to trap and destroy them. It’s my belief that they have been testing our defences and reconnoitring the ground in preparation for a larger operation. A few days ago I had that confirmed in a report from the strategos of the nomes on the border with Nubia.’

Macro looked at Cato and cocked an eyebrow. He cleared his throat. ‘Excuse me, sir. What do you mean by these, er, nomes?’

Petronius looked at him irritably and shrugged. ‘Should have known you weren’t familiar with arrangements here. It’s a hangover from the time before Rome made Egypt into a province. The nomes are administrative districts. Each one is under the control of a strategos and a local council. They did a good job of collecting the taxes and taking care of local legal matters so Rome saw no need to change things.’

Macro grunted. ‘Glad to see the Greeks got something right.’

‘Actually, the Greeks adapted the system from the natives.’

‘What? The gypos?’

Petronius smiled. ‘You really have no idea, do you?’

‘About what, sir?’

‘This province. Egypt was a great power once. Long before Rome was even a tiny village of farmers scratching a living on the banks of the Tiber.’

‘Bollocks.’ Macro jerked his thumb towards the heart of the city. ‘That lot?’

‘It’s true, I assure you, though don’t ever attempt to get one of the locals to tell you the full story, unless you have a few years to spare.’

Cato coughed. ‘Sir? About the Nubians?’

‘Oh yes.’ Petronius refocused his thoughts. ‘The strategos at Syene. Anyway, he sent several spies across the frontier to gather intelligence. Most didn’t come back, then at last he heard from one. The man had seen columns of Nubian warriors massing a hundred miles or so beyond the cataract. They were led by Prince Talmis. He’s the eldest son of the King of Nubia. He’s already extended their kingdom into Aethiopia and has quite a reputation as a general. He means to enhance it by attacking this province, I’m certain of it.’

‘But why?’ Cato asked. ‘Have the Nubians been provoked?’

‘In a manner of speaking,’ Petronius admitted. ‘A year ago, the Emperor ordered me to send a survey to map the Nile to its source. I advised him that such an expedition would cause friction with the Nubians. They’re a touchy people.’

‘No doubt. I would imagine they suspected this was a prelude to invasion. Why else would Claudius want the area mapped?’

‘The imperial secretary gave me his firm assurance that there are no plans to invade Nubia. The purpose of the expedition was purely scientific.’

Macro scratched his cheek. ‘And you believed Narcissus, did you, sir?’