Macro noticed the surprised look on the optio’s face and continued irritably, ‘Don’t tell me our Essene friends are going to take exception to sharing a whole bloody sea with me?’

‘No, sir. It’s not that, it’s just-’

Macro cut him off.’See to the men and their mounts.’ He turned to Cato. ‘Coming?’

‘Oh yes.’ Cato smiled. ‘I wouldn’t miss this experience.’

From the corner of his eye Macro saw Cato exchange a knowing look with Symeon and turned on them suddenly. ‘What?’

Cato feigned innocence. ‘It’s nothing. Let’s go and swim.’

The two officers stripped down to their tunics and boots and descended the stony slope to the shore. They picked their way a short distance along until they found a stretch of pebbled beach and undressed, leaving their clothes, belts and daggers on top of a rock. Macro trod warily down to the edge of the water and began to wade out, under the amused gaze of his young friend.When he was up to his waist Macro raised a hand and rubbed his fingers together.

‘Odd . . . Feels kind of oily.’ He raised his fingers and sniffed them for a moment before dabbing them with his tongue. At once his face tightened into a grimace. ‘Ugh!’

‘What is it?’

‘The water. It tastes awful. Far too salty.’

‘Then don’t drink it,’ said Cato. ‘Just swim in it.’

‘For someone who is such a poor swimmer, you’re awfully keen to get stuck in.’

Cato laughed. ‘You’ll understand in a moment.’

Macro was too weary to continue playing Cato’s games and turned away. Stretching his arms out he thrust himself forward into the gently lapping sea. Instead of plunging down beneath the surface he bobbed up like a cork. As soon as he tried the first stroke his legs seemed to come up out of the water behind him.

‘What the hell is going on?’

Cato laughed as he waded out towards his friend, and was treading water even before the sea came close to his shoulders. It was a strange sensation and he smiled in delight. Macro was still floundering, trying to swim a few strokes further out from the shore.

‘This is ridiculous.’ He gave up and turned on to his back. Floating effortlessly, he looked at Cato. ‘I suppose this is why it’s some kind of natural bloody marvel.’

Cato settled into the water and raised his legs. ‘Strange, isn’t it?’

Now that he had got over his surprise Macro found that the experience was quite agreeable after all and for a while he experimented with propelling himself around, finding that the best way was to stay on his back and use his arms like oars. Cato followed his example, whooping like a small boy.