Burrus turned in his saddle to survey the men of the Sixth Century. Before he could speak, Tigellinus stepped forward. ‘I volunteer, sir!’

Burrus opened his mouth, as if to speak, then shrugged and nodded. Cato felt his muscles tense as the centurion paced forward, between two of the German bodyguards. He stopped a short distance from the Emperor and there was a brief pause before Claudius offered the spoon up to his mouth. Tigellinus leant forward and consumed the mouthful. His jaws worked briefly and then he swallowed. There was another pause before Claudius arched his eyebrows. ‘Well?’

‘Bloody tasty, sir!’ Tigellinus barked.

‘No ill effects?’

‘None, sir.’

‘Very well.’ Claudius waved him away and Tigellinus backed off through the cordon of German bodyguards. Cato let out a pent-up breath and felt his body relax.

‘We’ll have some of this delicious cake and then return to R-r-rome,’ the Emperor announced. ‘Tribune, you may order your men to stand down while I eat.’

‘Praetorian Guard!’ Burrus called out. ‘Fall out!’

The guardsmen, on reduced rations, looked on enviously, having moved off a short distance to allow Claudius and his small retinue to pick at the cake and indulge in small talk. Cato noted with a smile that Narcissus was doing his best to insert himself between his master and the engineer and respond to the words of the Emperor with his customary obsequiousness while frowning frostily at every comment made by Apollodorus.

Macro was staring wistfully at the cake. ‘I could murder some of that.’

‘It looks far too rich,’ Cato responded dismissively. ‘Probably give you indigestion.’

‘I could live with it.’ Macro tore his gaze away and looked at his friend. ‘I was a bit worried there, when our friend Tigellinus stepped up to test the food.’

‘Me too. Seems I was right. Whatever his plan is, it doesn’t involve suicide.’

‘Except by indigestion.’ Macro turned to look for the centurion as he and Cato leant on their shields. Tigellinus had moved a short distance off and had unfastened his chinstraps and removed his helmet. He mopped his brow and then began to unbuckle his breastplate. He glanced briefly back up the vale with a strained expression. Easing his armour on to the ground, Tigellinus stretched his shoulders, raising his arms into the air.

Macro turned back to look at the small party of dignitaries crowded around the cake, scooping away at the choice ingredients. His stomach grumbled loudly enough for Cato to hear and the two exchanged a smile. Cato opened his mouth to comment, but before he could speak a dull crash reverberated through the air. Everyone turned in the direction of the sound. A moment later there was another crash that merged into a cacophony of splintering timber and falling rocks. Then a rushing roar that swelled up and filled the air. A sudden breeze stirred at the end of the vale, and strengthened.

‘What the fuck is that?’ Macro turned towards the din.