He pointed to the small dresser which stood between two pillars. I obeyed.

‘No, not for me!’ He barked as I started to fill a second cup. ‘You may be my kinsman, but it doesn’t mean I trust you.’ He held up his finger, displaying a large amethyst ring. ‘I carry poison in this ring, and you could do the same. Come on, sit in the chair. You look sly enough, Parmenon, but have you the brain to match? Tell me what you would advise, kinsman?’

I sat on the stool a few paces from him.

‘If you send an ordinary messenger,’ I replied, ‘the Emperor may still misunderstand.’

‘What do you know of the Emperor?’

‘Very little, your Excellency. I am merely a speck of dust under his sandal.’

‘Yes, yes, you are and I am that sandal.’

‘Then, Excellency, I would advise that you send the only witness to the incident, namely myself.’

Sejanus clapped his hands. ‘Very good, Parmenon. You will leave by trireme first thing tomorrow morning. You’ll go dressed in a tunic and sandals, with a cloak and nothing else.’ He paused. ‘Agrippina will try and give you a letter. What do you do then?’

‘I’ll be reluctant to accept it so she’ll bribe me. I will take it and hand it over to one of your men.’

Sejanus’s face crumpled into a smile.

‘Good and when you get to Capri?’

‘I will tell the Emperor, the Divine One, exactly what I told you: that Agrippina is becoming hysterical and Metellus was innocent of any crime.’

‘And the rest is up to your sharp wit. However,’ Sejanus picked up the wax tablet and pointed to where the secret door was, ‘my servant will accompany you. Give him Agrippina’s letter and he will study it carefully. He will also be my witness at your meeting with the Emperor so he’ll be able to report everything that you say. Be warned, when you go into the Emperor’s presence, make no reference to any religious belief or astrology. You must kneel and not raise your eyes. Above all, do not hold the Emperor’s gaze. He believes it’s one way demons can enter his soul. If possible, study the Divine One closely. When you return to Rome, I want to know everything you’ve seen and heard. Oh, by the way, Parmenon.’ He pointed to the goblet I was cradling. ‘That’s the very best Falernian, so drink it up.’

I did so quickly.

‘You are safe for now,’ Sejanus murmured. ‘However, my servant has his orders and if he suspects you of the slightest treachery towards me, you’ll never see Rome again. You may go!’

I was at the door when he called my name. I turned, to see that Sejanus was now sitting up on the edge of the couch. His face had lost that gentle conspiratorial look.

‘You did very well, Parmenon. Much better than I expected. You should celebrate with more wine tonight. You are a very lucky man.’

A guard took me back to Agrippina’s quarters. Darkness had now fallen and the gardens were lit by torches and lanterns. Praetorian guards patrolled in full view whilst others were hiding beneath cypress trees, in porticoes or recesses in the walls. My guide, a Praetorian officer, was dressed in half-armour and stank of sweaty leather. As we went through a side door leading to Agrippina’s quarters, the man hauled me into the shadows. I heard the scrape of metal and felt a sword tip press into my throat just beneath the chin.

‘What’s this?’ I murmured. ‘I have done no. .’

The man pushed me up against the wall.

‘Can you be trusted?’ he asked.

Gods, I was on the verge of hysteria! ‘Trust?’ I yelped. ‘In this viper’s nest? Trust whom?’

‘Leave him be,’ a woman’s voice urged.

The man stepped back.

‘You have a few minutes,’ he whispered and left, closing the door softly behind him.

Agrippina stepped out of the darkness. She was swathed from chin to toe in a dark-blue military cloak smelling of horse piss and stables.

‘Quickly, tell me all!’ she urged.

‘I could have been killed!’ I hissed. ‘You knew Sejanus wouldn’t believe your story.’

‘Of course I did,’ came the calm reply.

‘You could have told me what to say.’

‘Now, now, Parmenon.’ Agrippina’s pale face peered at me. She stood on tiptoe and kissed me on the lips. ‘You are like a gladiator returning from the arena and complaining that you have won. If you had been killed what use would you be to me? I told you to tell the truth. You did so and survived.’

‘Why did you kill Metellus?’ I demanded.

‘That’s one thing Sejanus doesn’t know. I suspected Metellus had heard me complaining of Sejanus so he had to die. It was also a way of bringing both myself and you to Sejanus’s attention. That’s the way of things, Parmenon. When you deal with the blood imperial, you either survive or go into the dark. Metellus had to die. I had to catch Sejanus’s eye. He’s not going to let me go to Capri, is he? He’s going to send you?’

‘How did you. .?’

She laughed softly. ‘It’s the only logical thing he could do.’

‘What about that guard?’ I pointed to the door.

Agrippina put her arms round my neck. ‘He loves me, Parmenon. He fought with my father in Germany. He’s held Germanicus’s daughter in his arms, fondled my breasts, run his hand in the secret part between my legs. He’ll die for me if necessary.’

‘But you are married?’

‘Oh, Parmenon, you are such a fool.’ She pressed her body against mine. ‘And yet you are doing so well. We are here to survive, Parmenon. I’ll fight with every weapon I have.’ She let her arms fall away and stepped back. ‘Can’t you see that? Now you are off to Capri, where you are to tell the Emperor the truth: that I murdered Metellus because I was hysterical.’ She clicked her tongue. ‘Did Sejanus do that?’

‘Yes, he did.’

Agrippina laughed. ‘So, what’s the next step, Parmenon?’

‘I am to leave tomorrow. Any letter you give me must be handed over to the Minion.’

‘Sejanus really thinks I’m a hysterical, stupid woman!’ The words were spat out, each one full of hate and malice. ‘One of these days,’ she added, ‘I’ll make him face the truth.’

‘Why did we have to meet like this?’ I asked. ‘In the dark?’

‘Because they’ll be watching you, Parmenon. If you came straight back to report to me, they’d suspect your allegiance. So, come and see me tomorrow morning before you leave. I’ll give you the letter to the Emperor and something else.’

She brushed by me and was gone. The door opened and the Praetorian officer stepped through. He took me by the elbow and pushed me up the steps, along to the servants’ quarters, a refectory with trestle tables and stools. The Praetorian introduced me and turned to where a greasy-handed cook stood at the end of the kitchen.

‘He’s got loose bowels,’ he sneered. ‘Either that or he’s so frightened he almost crapped himself. Give him something light to eat.’

He joined in the general laughter and left, satisfied that he could explain the slight delay in bringing me from Sejanus’s chamber to this refectory, where possibly every man, woman and child was in Sejanus’s pay. I ate some highly spiced stew and rye bread. I remember the meal well: I found it so difficult to eat, my hands kept shaking from fear and elation. I felt as if I had been put through a fire but come through unscathed.

A sleepless, restless night followed. In my dreams the ghouls clustered in. I was walking through Rome but every street and lane flowed with blood. Sightless eyes in severed heads perched on pikes gazed beseechingly at me, their lips still moving, spurting out blood as well as guttural sounds. I woke in a sweat, took some wine and returned to a more peaceful sleep. I once discussed such nightmares with Domina. She winked and nipped my cheek.

‘It proves you have a conscience, Parmenon,’ she mocked.

‘Don’t you dream, Domina?’

‘I sleep like a baby,’ she replied.

The next morning she certainly looked unruffled and unperturbed, when a servant took me up to her quarters. The room where Metellus had died was now cleaned and cleared. Servant girls thronged about, so I had to be prudent: most of them, if not all, were in Sejanus’s pay. Agrippina played her part to perfection. She led me over to a window recess and took a small scroll from beneath the shawl round her shoulders. She glanced down into the courtyard.