The men of the Fifth and Sixth centuries marched up to where Tribune Burrus was waiting, mounted on an immaculately groomed black horse. When the column stood ready he waved a hand towards the gate and the leading rank moved off. They entered Rome and marched down to the palace where the imperial retinue joined the column before it marched back out of the city and headed towards the lake, over ten miles from the capital. The Emperor was attended by fewer advisers than usual, Cato noticed. There was Narcissus, but no sign of Pallas or the Empress, or the two boys.

The rain-washed countryside smelt fresh and the warmth heralded the coming of spring. The first buds were emerging on the branches of many of the fruit trees lining the route. The litters carrying the imperial party were between the two centuries of Praetorians and from the rear Cato could just make them out when he craned his neck to look over the gleaming helmets and javelin tips rippling ahead of him. As the column passed between small villages, the inhabitants came to watch their Emperor pass by and offered a cheer as Claudius raised a hand in greeting. On either side of the litters marched the German bodyguards, their barbarian appearance unnerving the more timorous villagers.

They reached the lake in the early afternoon and the men were allowed to fall out of line and rest while the Emperor and his advisers inspected the preparations for the Naumachia. The imperial grandstand was nearly complete, constructed on an artificial mound that had been raised at the edge of the lake. Along the shore carpenters were hard at work preparing the barges and river craft that had been hauled up from the Tiber to serve as the two fleets that would battle it out on the waters of the lake. Makeshift masts rose from the decks of the vessels with spars, sails and rigging that were more decorative than functional. Rowing benches were fixed along the sides and stout rams attached to the bows of each boat. From a distance they might pass for the warships of the Roman navy, but on a much reduced scale. A quarter of a mile away from the activity on the shore of the lake stood the stockades where those who were to fight were to be held for the duration of the spectacle.

‘Unbelievable,’ Macro commented ruefully as he and Cato surveyed the scene from a rocky outcrop a short distance from where the men of the escort relaxed on the verdant grass either side of the road leading back to Rome. ‘I’ve never seen anything like it. It looks more like the preparations for a major campaign than a bloody gladiator show.’