The truth of it was that our losses were heavy enough – not just battlefield losses, either, but dysentery and other sickness, accident, weather – that most of us who had brought our own grooms were not above putting them in dead men’s armour and using them to fill our ranks. The sort of distinctions that mattered enormously in lowland Macedon – birth, horse quality, armour – either mattered not at all in Asia (such as birth) or were gone (horse flesh and armour). We were all mounted on Asian horses and almost every Macedonian cavalryman regardless of social status now had a full thorax, a good helmet, a lance and a couple of javelins, a sword – and like as not, gold on his bridle and silver in his scrip.

Polystratus’s promotion mirrored mine. I arranged for all of my grooms to be formally taken into the companions, and Polystratus was then formally my hyperetes, as Niceas served Kineas. And my troop returned to near full strength of over a hundred riders. I got Coenus’s troop, as well – he was going home to Macedon with the newly married men, a move that restored the king to popularity with the rank and file, because it looked normal – the married men were supposedto go home every winter.

In fact, I was beginning to fear that the king didn’t really care what happened in Macedon. War in Asia was self-perpetuating – we were making about as much money as we needed to maintain the army, and even to increase its size. We were locked in a competition with Memnon for the service of all the mercenaries in the Greek world, and we were fighting for our lives, and Alexander loved every heartbeat of it. Why go home? What did Macedon have to offer?

Also worth noting is that as long as we were fighting for our lives in Asia, no one was going to plot against the king – well, except Parmenio, and he was right there where he could be watched.

And Olympias was a long way away, too.

Coenus marched away with the married men, and Parmenio marched away with the left wing. He went back to Sardis, as he had wanted to all along – paid off some mercenaries, and then took the rest with the siege train and began a leisurely mopping up of mountain tribes north and east of Sardis.

Alexander marched away along the coast, bypassing strongholds still held by Memnon. He had the hypaspists, the Aegema and the unmarried pezhetaeroi, and the scouting cavalry. I heard from him quite regularly for about four weeks – he seized Telmessus by a stratagem, and gave it to Nearchus to hold.

I like to think that Alexander had tired of Nearchus’s constant sycophancy, but it’s worth noticing that he’d sent me away, too.

I had four thousand men and plenty of slaves – I had seized the best portion of the city and had my men rebuild the houses. I inspected the work every day, and in two weeks we were the best-housed army in Asia. Then I kept them at work, rebuilding the temples and other houses, and after another week surviving citizens started to return.

I also sent Kineas to find the Athenian squadron and beg or borrow some engines and an engineer.

By the gods, he did me well. He came back in two weeks with ten heavy engines – or rather, the bronze parts for them – as well as Helios, a freed Cyprian slave, who had all of the problems of Pythagoras in his head and knew how to construct . . . well, almost everything. He’d been serving the Athenians as a dock builder, and he was bored. I offered him the Macedonian rate of pay as an engineer, and he signed on the spot. He was short, very short for a man, and his skin was deeply tanned, almost the colour of old wood. He had curly blond hair – hence his name – and a pleasant face. He’d been well born, but taken by slavers as a boy and treated badly.

He looked at the three island citadels off Halicarnassus, and shrugged.

‘Three ways to take ’em,’ he said. He ticked them off on his fingers. ‘Build a fleet and storm ’em, starve ’em, or grow wings and fly there.’

I nodded. ‘I agree,’ I said.

He grinned. ‘Good. I was afraid you expected me to make something out of nothing.’

I shook my head. ‘My plan is to start with the easiest and move from there. Caunus and a town called Knidos.’ I shrugged again. ‘Never seen them myself, but they haveto be easier than this.’

In fact, Thaïs had people in both, plotting revolution.

It was great fun, the two of us planning a complete campaign together. I’ve known men to freeze in high command, and it is different, but it wasn’t my first time, and she liked it too, and it was something we did together. And because she was working for me, and not for the king, I began to see howshe ran her net of informants, and to watch the details of her intelligence-gathering.

For strategic intelligence – the news of politics, of the thoughts and intentions of great men and cities, of the Persian court, of the satraps – she had her web of letter-writing friends. They didn’t think of themselves as spies, and in fact she called them her Epistolaroi. And the greatest and most important of the Epistolaroi was the Pythia and her priests at Delphi.

For tactical intelligence – the immediate collection of information on local troop movements and enemy intentions in the near term, our scouts did most of the collection – most, but not all, because by this time, after almost a year in the field, Thaïs had a corps of spies she called the Angeloi, the heralds. Strakos led them, and they were mostly freemen. Their characteristics were unarmed anonymity, and superb horses. We knew every one of them by name and by sight, so that they could come and go from our lines without passwords. They seldom carried weapons openly, and they rode far and fast, gathering news. Every one of them had funds to buy information, and most of them had the personal skills to recruit their own informers on the spot.

And above all of them was Thaïs. She read every report, spoke to the returning cavalry patrols, interviewed the Angeloi, read the letters from the Epistolaroi and answered them. It was an enormous workload, but she had a secretariat of slaves and freemen, most of them taken at Granicus – slaves who read and wrote Persian, or Thracian, or Aegyptian, or Carian. All told, her establishment had a hundred people working for it, men and women. It was nota miracle of efficiency, because it was more like art than science, but her information was reliable and quickly gathered.

In the fourth week, I took a cavalry reconnaissance down the coast, with the Angeloi out in front and detailed reports on the towns already in my head, and Caunus looked the easiest, on paper and in fact. Knidos sat on the end of a 250-stade long peninsula with a mountainous spine. Riding cautiously along the coast road, or rather the coast goat path, I could see an ambush site every five stades. By pure good luck and with some tips from Thaïs’s friends, we caught about a quarter of the garrison of Knidos outside their walls and captured them. And then, reversing Alexander’s policy, I hired the lot of them, and didn’t execute them. I wanted to make it easyfor men to surrender, not hard.

Caunus, on the other hand, sat three-quarters surrounded by land – flat, well-earthed land. Helios got off his horse in the dawn – we were moving fast and light – and crawled right up to the city wall, and he returned convinced that he could tunnel under the walls in a week.

We got back to Halicarnassus late in the evening, after dark, soaked and very cold. I rode into the courtyard of my house and found it in near panic.

Queen Ada had come into my house in Halicarnassus without being announced. The cold rain poured down the gutters of the house and spat out on to the ground, and I was in a surly mood – I wanted to throw Thaïs on a bed – or a warm floor – and I didn’t want to deal with this woman.

It wasas bad as I feared.

‘Why has he not written to me?’ she demanded as I entered the room.