The lavish banquets ceased and Agrippina became more reclusive. Claudius and his freedmen were now invited to little private supper parties where Agrippina and the Emperor could converse closely together. Claudius was full of anger about his wife’s conduct, but Agrippina quietly reminded Claudius of Styges’s prophecy, gently coaxing Claudius to let the adulterous pair have their heads. The Emperor submitted and, when Messalina’s infatuation with Silius only deepened, Claudius’s powerful ministers, Narcissus and Pallas, entered the game.

Claudius was persuaded to go to Ostia to make sacrifice, and whilst he was away, Agrippina moved into the imperial quarters as the guest of Pallas. At last Agrippina was able to drop her mask and invited Narcissus, Pallas and myself to a secret meeting.

‘This is truly ridiculous,’ Agrippina began. ‘The Emperor, my Uncle Claudius, is being made a cuckold, a public laughing stock.’

Of course, she made no reference to her own involvement in this affair or the way she’d persuaded Claudius to turn a blind eye to what the rest of Rome was talking of. Pallas and Narcissus needed little encouragement: they were tired of Messalina, fearful of her terrible rages. If the opportunity presented itself, they were both prepared to strike speedily and ruthlessly.

‘I have heard rumours,’ Agrippina said. ‘That Messalina and Silius intend to marry.’

Narcissus and Pallas cried out in disbelief.

‘It is true,’ Agrippina insisted. ‘They are going to hold their own Bacchanalian festival and celebrate a marriage both unlawful and impious.’

After intense discussion, it was agreed that, if such a ceremony took place, Claudius should immediately confront his wife. Messengers were sent speeding off to Ostia, beseeching Claudius to return, and Agrippina and the freedmen met him in the Praetorian camp outside the city. They produced witnesses who described in every detail Messalina’s affair with Silius, their proposed bigamous marriage and a litany of previous infidelities. Claudius, trembling, at first panicked.

‘Am I still Emperor?’ he demanded of Narcissus and Agrippina. ‘Will Silius become Emperor in my place?’

Agrippina calmed him down and advised him precisely what to do.

The information Agrippina had gathered about Messalina’s activities, proved to be astonishingly accurate. Messalina and Silius, their brains turned by arrogance and lust, performed a marriage ceremony in the palace grounds, acting out the rituals of a grape harvest. Messalina and her female friends were garbed in animal skins, as if they were Maenads, whilst Silius and his cronies were dressed as satyrs. Frenzied in their drunkenness, they threw all constraints aside: men and women made love to each other in the shade of trees in wine-induced orgies, three or four men taking one woman, their performance watched and cheered by the others. Agrippina’s spies reported back to the Praetorian camp, and, by late afternoon, Claudius had recovered both his wit and his courage.

Helped on by Agrippina, rumours of the Bacchanalian orgy, with particular emphasis on Messalina’s conduct, spread amongst the guards. Outraged tribunes demanded an audience with the Emperor, insisting that the illicit celebrations be stopped and the participants ruthlessly punished. Claudius, hectored by Agrippina, quietly agreed. Soldiers were despatched into the palace grounds, bringing the revelry to an abrupt end as both Satyrs and Maenads fled for their lives.

The guards hunted the revellers through the trees and into the streets. Some were executed immediately, others were loaded with chains and taken off to prison. As the wine and opiates wore off, Messalina panicked and fled to the house of the Chief Vestal Virgin, begging her to plead with the Emperor. The priestess refused. The Empress of Rome, the beautiful Messalina, still dressed as a Maenad with fading garlands round her neck, was reduced to running from one end of the city to the other, vainly imploring former friends for help. No sympathy was shown and she tried to leave Rome in a cart used for removing garden rocks.

At the Praetorian camp Claudius was wavering. Agrippina whispered hoarsely to me that if the Emperor changed his mind we would all have to flee from Messalina’s undoubted fury. She conferred quickly with Narcissus and Pallas but was openly alarmed when a guards officer announced that the Empress had appeared at the camp gates, an arm round each of her children, Britannicus and Octavia. The guards let her in and Messalina threw herself on the Emperor’s mercy. I lurked in a corner of the imperial pavilion and saw that Messalina was using all her beauty, charm and eloquence to gain a hearing.

The Chief Vestal Virgin arrived, pricked by conscience, to argue that a wife should not be executed unheard. Narcissus and Pallas intervened, rudely telling the Vestal to return to her religious duties. The old woman, frightened, mumbled an apology and withdrew. Narcissus now attacked Messalina, saying she was unfit to be a mother and ordering Britannicus and Octavia to be taken away from her. He crouched and whispered in the Emperor’s ear that Messalina had effectively divorced him by her impious marriage to Silius. Then, his voice rising, he started on a long list of Messalina’s former lovers. Claudius could do nothing but cry, shake his head and moan loudly.

Messalina shouted at Narcissus to produce proof. The Emperor glanced expectantly at the freedman who was unable to answer until Agrippina decisively intervened. She hastily wrote a short note and passed it to me. I read it quickly then handed it to Narcissus. His podgy face, red with embarrassment, eased into a smile, and he bent down again and whispered in the Emperor’s ear. Agrippina had given him all the proof he would need.

‘We will go to Silius’s house,’ Claudius declared, lurching to his feet. ‘And seek the necessary evidence.’

Once we’d arrived at Silius’s house, Narcissus, prompted by Agrippina’s note, pointed out all the items from the imperial palace, gifts from the Empress to her lover, that were crammed into every available corner. Claudius was a greedy, acquisitive man, and when he saw the statuettes, vases, precious cloths and other items brought out and laid at his feet, he issued orders for the arrest of Silius and all his companions and returned to the camp. Once there a hasty platform was erected and the captives brought in. Unluckily for Messalina, they did not challenge the accusations but simply asked for a speedy death. One by one they were hustled from the platform to be decapitated by guards. They all died bravely except the actor Mnester, who begged for his life.

‘Others,’ he whined, ‘have sinned for money or ambition; I was simply compelled to.’

‘Are we to stand here and listen to this rubbish?’ Narcissus barked. He pointed to the execution grounds now strewn with bleeding, decapitated corpses. ‘Others have died, why spare an actor?’

And Mnester went under the sword.

Once the executions were finished, Claudius insisted on being taken back to the palace, where he ate and drank and grew maudlin over Messalina.

‘I’ll see her tomorrow,’ he declared tearfully. ‘I’ll listen to her explanation.’ He became more and more befuddled, his anger cooling, his lust for Messalina resurfacing.

Pallas reported to Agrippina that Claudius had started to refer to Messalina as ‘that poor woman’.

‘She cannot live till morning,’ Agrippina declared. ‘Where is she now?’

‘She has fled to the gardens of Lucullus.’

‘Then let her die there. Parmenon,’ Agrippina ordered. ‘Go and see her. Tell her the Emperor’s heart has not changed. Pallas, she must be dead by nightfall.’

Reluctantly I left. No, that’s a lie, I wasn’t reluctant: if Messalina survived, she’d claw her way back into Claudius’s affections and both my head and that of my mistress would roll. Whether I liked it or not I was in the amphitheatre facing a fight to the death. Our opponent was down and I could almost hear the roar of the crowd, ‘Hoc Habet! Hoc Habet! Let her have it!’