He approached the main gate of the imperial villa at the top of the track and told the duty optio his name and rank and explained his request to see Narcissus and make his report.

‘Wait here, sir,’ the optio instructed and unhurriedly climbed the stairs into the villa. A cold wind was blowing over the island and gathering clouds threatened rain. To the north the hillside tumbled steeply down to the cliffs overlooking the sea and Cato stared over the bay towards the distant headland of Puteoli. A hundred or so miles further along the coast lay Ostia, and a short ride into Rome, and Julia.

‘Prefect!’

Cato turned and saw the Praetorian optio beckoning to him from the top of the stairs. The guards on the gate parted to admit him. Then, at the foot of the stairs, another guard raised a hand.

‘Excuse me, sir. I take it you have handed your sword and any other weapons in to the port guards?’

‘Yes.’

The guardsman nodded. ‘Good. Then there’s one last search before you proceed, sir. Please raise your arms and stand still.’

Cato did as he was instructed and the guardsman expertly frisked his cloak, tunic and ran his fingers around the inside of Cato’s belt before he stood back. ‘That’s it, sir.’

Cato advanced and climbed the stairs to the waiting optio, who led him through a marble portico into the atrium of the villa. The space was dominated by a large shallow pool with a tessellated image of Neptune and shoals of fish decorating the bottom. On the far side a short colonnaded hall led out on to a terrace. Through large doors to the right, Cato could hear voices, laughing and talking light-heartedly. There was a smaller opening to the left, leading down to the quarters of the slaves and lesser officials.

‘This way, sir.’ The optio gestured to Cato, who followed him across the atrium and down the corridor on to the terrace. A wide expanse of pink-hued marble stretched out before them and ended abruptly fifty paces away. Potted plants and trellised walkways surrounded the terrace, which afforded spectacular views across the sea towards the mainland. Cato could understand why the island had been the favourite playground of the imperial family for so many years.

There was only one other man on the terrace and he sat on a bench with his back to Cato.

‘There you are, sir.’ The optio halted and indicated the seated figure. ‘I’ll see you back at the gate, sir. To log you out.’ The optio saluted and turned and marched into the villa. Cato continued across the terrace. Narcissus’s thin frame was wrapped in a plain red cloak and his dark hair was threaded with grey. He glanced back as he heard Cato’s footsteps and offered a smile that lacked any real warmth.