‘There was a frost the other night. It will have done the spring vegetables no good.’

Volusianus had never hidden his peasant origins. If anything, he drew attention to them. Some claimed it was vanity, to point out just how far he had risen. A personal favourite of Valerian, the previous Emperor, Volusianus could not have climbed higher: through the ranks of the army, admitted to the equestrian order, appointed Praetorian Prefect, granted senatorial status. The capture of Valerian by the Persians had not stopped his ascent. The Emperor Gallienus, Valerian’s son, was said to rely upon him. Certainly Gallienus had confirmed him as commander of the Praetorians. Indeed, Gallienus had shown the former peasant the signal favour of holding the office of consul with Volusianus. For eternity, the one thousand and thirteenth year since the founding of the city of Rome would be known as the year when Gallienus and Volusianus were consuls. It was a proud form of immortality.

Loyalty and ruthless efficiency were the public qualities that underpinned the meteoric career of the Praetorian Prefect. Of course there were rumours. But, looking at that open and guileless rustic face, Murena found them hard to credit. There were always unfounded rumours. Anyway, Murena owed his own office to Volusianus.

Another knock at the door.

‘Gnaeus Claudius Severus,’ the guard announced.

The officer saluted as the door closed behind him.

‘We will do what is ordered, and at every command we will be ready,’ Severus said.

After the formal words of a soldier to his superior, no one spoke. Severus remained standing at attention. Volusianus regarded him closely, like some physiognomist trying to read his innermost soul.

Murena half recognised Severus. He had seen him before – years before. The stubby beard and short hair, the grey eyes, the slightly sticking out ears; all were familiar, but Murena could not place from where.

The silence stretched, was fast becoming oppressive.

Murena kept his face expressionless. What was this about? Was it the arrest of a traitor, the promotion of a deserving officer, or something altogether more sinister? There were no guards in the room, and Severus was armed. It was unlikely to be the detention of conspirator.

A horrible suspicion surged up, like a monster emerging from the depths. Was the man detained to be Murena himself? Would he be dragged to the cells and subjected to hideous tortures? In the twilight world of the frumentarii no one was above suspicion; innocence was no guarantee of safety. Murena pushed the thought back down into the darkness.

‘You are Gnaeus Claudius Severus, son of Publius, an equestrian from Samosata in Cappadocia.’ Without pausing for an answer, Volusianus continued. ‘You have commanded the First Aquitanian Cohort in Britain, the Third African Cavalry in Germany, and the Second Thracian Cohort in Syria.’