Another quotation! There was a faint rustling and the mysterious messenger had left. I stood, my hand going to my mouth. That bitch Salvara! She was obviously in Nero’s pay, and had only to wait for Agrippina to send for her. She’d done exactly what that copper-headed monster had told her to. Without her words, Agrippina would never have come to Baiae. Salvara had blinded my mistress, given her false hope, baited the trap and Agrippina had walked straight into it. The two quotations were a warning: put together, it became clear something dreadful was to happen at sea. Even Salvara’s reference to a ‘master of the sea’ agreed with this. An accident, in fact murder, was planned. Once it was over, Salvara’s warnings would be used to demonstrate that Agrippina’s tragic death was fated. Years later, I caught up with the old bitch and cut her throat.

I spent that night tossing and turning. Once it was daylight, I went for a walk in the mist-strewn gardens. The musicians had long retired whilst the slaves and servants were helping themselves to the remains of the feast. Of the revellers there was no sign, but a chamberlain assured me that they had all been carried to their beds. I went across to Agrippina’s villa: she, too, was sleeping.

The rest of that day was what I’d call a ghost day. The sun didn’t show itself till the afternoon. Matters were not helped by an eerie atmosphere in the imperial villa. Nero didn’t appear until, white-faced and red-eyed, he paid a courtesy visit to Agrippina. They cooed and laughed together until he left, saying the bireme would be ready later that day to return my mistress to her villa at Antium.

‘From there,’ Agrippina excitedly explained, ‘I travel to Rome. Apartments have been prepared for me in the Palatine Palace. We’ve had enough of the countryside, eh, Parmenon?’

She gave me a warning look. I nodded and made preparations to leave.

Darkness had fallen by the time we congregated on the beach. Two lines of Praetorians held torches to light the way along the shingle. It was a lovely, cloudless night, with the moon riding high and a stiff sea breeze proving a welcome relief after the perfumed air of the villa. I had not attended the small leaving banquet, which Nero had stated was a private affair. He escorted his mother down to the boat, holding her affectionately by the hand. The rest of the coterie gathered around as Nero embraced his mother, kissing her lips and bosom.

‘These breasts,’ he murmured, ‘once suckled me.’

Members of the court also made their farewells. They all ignored me except Burrus who clasped my hand and wished me health. I was about to pull away when he dragged me closer.

‘“With you”,’ he whispered, ‘“I would willingly live! With you I would willingly die!”’

I couldn’t make out his face in the darkness yet I recognised this further quotation from Horace. Danger was all about us.

‘Iacta alea est!’ I replied. ‘The die is cast!’

I joined Agrippina and the rest as we were taken out to the waiting bireme. I clambered aboard and stared around. The ship seemed seaworthy enough but no Praetorians were present and the captain and the pilot were not dressed in their usual uniform but in simple tunics and sandals. I glanced back towards the beach, where a ring of torches surrounded the would-be murderers. Even before it happened, I knew where the danger would come from. Agrippina stood in the prow, eyes fixed on the shore. Nero called out something. The breeze caught his words but it didn’t conceal the mocking laughter. Agrippina blew kisses and walked away to take her place on a couch under an awning in the stern.

Orders were rapped out, and the ship glided silently round. The slop of oars sliced the water rhythmically, each stroke measured by the captain marking the time. A breeze wafted across to us the smell of pines and perfume. The bireme picked up speed, cutting through the water. As the torchlight on the beach disappeared, a strange silence descended. Agrippina lay on the couch under the awning, with Acerronia kneeling on one side, and Creperius on the other. I walked along the ship, my eyes searching every corner. I could see nothing wrong. Had it been built to capsize? But that would endanger the lives of the crew as well. Were they in the plot?

‘Parmenon!’ Agrippina called. ‘Stop stalking like a cat, you are making me nervous.’

I ignored her. She called again, as I climbed the steps to where the captain and pilot stood. I tried to engage them in conversation, but they busied themselves about their duties. I walked to the rail and stared at the approaching bank of mist.

‘Why did no Praetorians accompany us?’ I asked. ‘A guard of honour?’

‘I don’t know. I was just given my orders,’ the captain grumbled.

I left the platform and went down the steps. Agrippina and Acerronia were discussing the events of the night before. Now and again Domina would break off to give instructions to Creperius over what to pack when they left for Rome. She was annoyed with me. I still felt tense at the sense of pressing danger. I looked up, to see that the captain had moved to the rail, and was staring out into the night. He carried a lantern lashed to a pole. Was he signalling?

‘Domina!’ I hissed.

‘Parmenon, either be sick, go to sleep, or sit down!’

The sea breeze shifted. I heard a slight creak, and the sound of oars. The captain on the bridge was waving the lantern. I raced up the steps and ran to the rail, staring out into the night. As the mist parted, I gasped in terror. A huge warship, a massive trireme, oars out, its prow carved in the shape of the cruel face of an eagle, was bearing down, intent on ramming the bireme.

‘Agrippina!’ I screamed.

Commotion broke out below, where some of the rowers had now glimpsed the monster which was about to smash us. I heard a sound behind and turned, drawing my dagger. Without hesitation, I thrust it straight into the pilot’s stomach. The half-raised club dropped from his hand as he slumped, choking on his blood. The captain lunged, flinging the lantern at me. I ducked to one side and lashed out with the dagger, cutting a deep jagged slash across his chest. I ran down the steps, but it was too late: the trireme struck us with a mighty crash. The awning covering Agrippina collapsed, and one of the poles dealt Creperius an ugly blow on the side of his head. I could do little for him. I pulled the awning up and dragged Agrippina from her couch. Acerronia was screaming, and I slapped her on the face, pulling her to the side. Figures loomed out of the darkness. The trireme was now pushing the bireme, threatening to either tip it over or crush it beneath its weight. The night air was rent with screams. I ripped Agrippina’s stola from her shoulders, pushed to the side of the bireme, already dangerously low in the water, and tipped her over. Acerronia and I joined her in the cold water.

‘Swim!’ I screamed.

Agrippina needed no second bidding. Light and swift as a dolphin, she struck out, putting as much distance between herself and the sinking bireme as possible. I followed, but Acerronia, behind me, was spluttering and calling out. Agrippina was a splendid swimmer, but Acerronia was not. I glanced back, saw lantern lights and heard the calls of officers on the trireme. Treading water, I saw Acerronia panic. She swam back towards the trireme, straight into the pool of light thrown by the torches and lanterns.

‘Help me!’ she screamed. ‘Help! I am the Empress!’

An oar moved towards her: the usual tactic employed to drag a man from the sea. Acerronia swam towards it. The oar moved viciously like a club and, instead of allowing Acerronia to grasp it, struck her viciously on the side of the head. Acerronia spun round. For a few seconds I glimpsed her white face above the water before she sank. Agrippina was calling out to me. I swam in the direction of her voice.