In just a few weeks, Alexander’s view of the world began to narrow perceptively.

Ironically, in the way that the gods move, Thaïs’s last great triumph came in such a way that Alexander was made to realise what he had lost. A few days after the sea monster, I went into my pavilion to find Thaïs deep in conversation with a handsome, older man with a salt-and-pepper beard and large blue eyes. He wasn’t tall, but had a magnificent bearing, and he sat in my tent as if he owned it. I was prepared to hate him on the spot, but he rose graciously, took my hand and thanked me courteously for his wine and the use of my couch.

He was, in fact, the King of Cyprus – absolute ruler of more than one hundred triremes. Thaïs had been making overtures to him for more than a year, and like a fisherman with a small boat who catches a big tuna, she’d spent all that time bringing him carefully ashore.

I was sent for by the king. He was sitting with Callisthenes, getting the news of the world. I loathed Callisthenes, who neither told the king the truth nor managed to be a decent lickspittle, but played both harlot and harridan. But he paid in the end. He was a poor philosopher and a sad comment on Aristotle, although I’ve heard men say that Theophrastus was Aristotle’s real favourite, although no blood relation. Perhaps.

To me, though, Callisthenes, even at the height of his power with the king, was a paid foreigner, not a soldier or a man of account in any way. So I brushed past his protests and crooked my finger at the king. ‘A matter of some urgency,’ I said quietly.

Callisthenes stood up.

‘Just the king,’ I said to him.

‘Who is it that sends for me?’ Alexander asked.

‘Thaïs,’ I said. ‘A matter of some urgency. And delicacy.’

Callisthenes shrugged. ‘Oh, then I mustcome,’ he said. ‘Anything of hers is my business.’

I caught Alexander’s eye, and he nodded. ‘No,’ he said to Callisthenes. ‘Wait here.’

We walked out together. I ignored Callisthenes’ outrage – I cared little for him then, or ever. As soon as we were clear of the guards, I said, ‘Thaïs has won over the King of Cyprus. He’s in my tent. He wants only your word on certain matters, and his whole fleet is at our service.’

Alexander stopped, looked at me and then gave me a brief embrace that hurt my burns. ‘A fleet!’ he said. ‘By the gods! Poseidon’s gift! A fleet!’

He went swiftly to my tent, embraced the King of Cyprus and the thing was done.

Afterwards, and many times, Callisthenes claimed that he had turnedthe King of Cyprus.

And it was the last political act of Thaïs’s life for a long while.

The Cypriot fleet changed everything. Alexander kept it hidden, up the coast, and put Craterus’s taxeis aboard as marines, and went aboard himself. Several evenings later, another beautiful late-summer evening, and the Tyrians descended on the end of the mole with fifty boats, grappling hooks and a barrage of covering fire from their engines on their walls.

Alexander sprang his trap, and the Cypriot fleet raced for the entrance to Tyre’s island port – a passage the length of a trireme wide, between two enormous stone towers bristling with engines.

We cheered like madmen as the king’s galley raced into the setting sun, but the Tyrians were canny, and they fled from the mole. We only took five of their ships, but dozens of their marines were left on the mole in the panic, and we killed every one of them.

At the command meeting later that night, I pointed out that neither of the towers had loosed so much as a rock at our ships.

‘The towers were empty,’ I asserted, and Diades nodded. And thumped my back.

The Tyrians were running low on men. Or rather, when they put fifty ships to sea with full rowing benches, that stripped their manpower.

And what that meant was that their fleet would never dare put to sea again. We had mastery of the sea.

Diades and Alexander put it to use that very night.

Boat raids. Twenty men in the bow of a trireme, or five men in a smaller boat, rowed up to the walls, attached grapples and the crew of the trireme tried, by rowing away, to force a section of wall to collapse. In other places we set fires, or tried to scale the wall.

Helios refitted pairs of triremes with huge platforms between them – like monster catamarans – mounting large siege engines. We’d done this at Halicarnassus, and now he did it on a larger scale. We built six of them, floated them and parked them opposite the weakest portion of the wall, just about a quarter of the circuit around the wall from the mole. In two days, they brought a section of wall down. We boarded ships for an assault, but the weather worsened and we had to abandon the idea, and the next day they had rebuilt the wall.

Two more days of pounding away, and we had to rebuild all of the engines on the ships while the enemy rebuilt their wall. And then we were at it again, and with a rush, their whole line of new masonry went down, despite hoardings, and the cover of great oxhides and a dozen other contrivances.

That afternoon, however, a pair of Cypriot triremes ran across a pair of Carthaginian triremes and they fought each other to near extinction. One of the Carthaginians limped away, and both of the Cypriot vessels were turtled, although both were reclaimed later and restored to service.

Now Alexander had to fear the appearance of a great Carthaginian fleet. We might lose our mastery of the sea at any moment. The mole was pressed forward. A man could almost jump the gap. The fleet was brought in close, and Diades had four of the oldest triremes brought up to the mole so that they could be filled with stones and sunk in the channel to act as piers for his mole.

But that night, a storm hit us like no other I had experienced. It lasted three days, and every tent in the camp blew flat. I had to rescue Thaïs, still weak from the loss of our child and still so depressed that she would take little or no action to save herself. I moved her to Isokles’ tent, and then, moments later, that too collapsed and I had to lift her out through more sodden silk and canvas.

The next day was no better, and the only standing shelters in the camp were the ones built from lashed boat sails spread over heavy timbers – and tied down by sailors. And that night, when the storm hit its height, even those fell, and we huddled together, taxiarchs and strategoi and pezhetaeroi and slaves, all together in our shared fear and misery. The gods have the ability to make one feel very small, when they wish. A good storm is humbling.

When we awoke on the third day, I followed Diades down to the shore to see what had happened.

The mole was gone.

Perhaps that is an exaggeration. Certainly, the sea was breaking over something, so the bulk of the earth and wood was still there, but the sea flowed over it, and it was enough to break your heart. His precious ships – full of stones, ready to be moved into position – were all gone, capsized and sunk in shallow water north of the mole.

‘Poseidon’s fury,’ he said.

‘And now we have it all to do again,’ I said.

Diades shrugged. ‘I have already stockpiled more stone than we had when we started,’ he said, with a grim smile. ‘It will go faster this time. But only if the king does not despair.’

That night, we had the stormiest command meeting I can remember.

The factions were fully developed. Parmenio, his sons and the older officers – men like Meleager who owed their careers to Parmenio, and men who were midland Macedonian landowners – and men who were tired of war.

The truth is, I should have been with Parmenio’s faction. I knew what was in the king’s mind. An abyss of endless war – a sort of infinite Iliad, with himself cast as Achilles, where an endless procession of enemies threw themselves on his heroism and his genius – and perished.