Claudius looked back at Cato, wide eyed, then past him, aghast. Cato grabbed the Emperor’s arm with one hand and wrenched at the toga with the other. At once the Emperor struggled and lashed out with his spare hand. ‘Help! Murder!’

‘No, sire! The toga will weigh you down!’ Cato shouted, ripping the thick woollen material from the Emperor’s shoulder. He heard Macro cry out a short distance behind, but before he could turn to look, the wave struck. There was an instant when he felt a surge around his calves, and Cato stepped in front of the Emperor, trying to shield him with his body. The full force of the water slammed into his back, instantly wrenching him off his feet. Cato tried to stay upright, kicking down to get purchase on the ground as he was swept along. He held tightly to the Emperor, pushing Claudius up. The water surged around his head, flowing over him and roaring in his ears before he surfaced, snatching a breath.

Something struck him in the ribs, a winding blow that drove the air from his lungs in an explosive cough and water instantly flooded his mouth before he could shut it. Then he was under again, still holding the Emperor and feeling him struggling wildly in his grasp. Cato felt something solid close by and risked letting go of Claudius with one hand as he groped. He felt the branch of a tree. He clamped his fingers round the rough bark and pulled himself and the Emperor towards it. His head burst through the surface once more and Cato took a breath. Around him was a chaotic mass of spray and water and debris, with the heads of men and flailing limbs all about. Cato thought he saw Macro a short distance away, but water closed over the head before he could be sure. Claudius came up, spluttering at his side.

‘Sire!’ Cato yelled into his face. ‘Grab the branch!’

Claudius turned his head to Cato. ‘I can’t! I’m being dragged down! S-s-save yourself, young man. I’m done for!’

Cato saw that his toga was still caught round his chest and debris in the surging water was pulling at the cloth and dragging the Emperor with it. Cato grabbed at the fabric and wrenched it as hard as he could, working it free. It slipped down a little, yet Claudius was still being pulled under and let out a despairing cry before the water closed over his face again. He came up and Cato shouted, ‘Kick it free! Kick it free, or you’ll die!’

‘Yes … yes,’ Claudius spluttered. ‘Kick it free.’