All of us were as skinny as children in a hill town and most of us had lice.

And we had wonall our battles.

But we’d been living like this since before winter – and habituated as we were, men’s bodies were starting to break down. As an example – I began to pull muscles – in my sides – every day, just climbing and letting myself down the mountains. Just walking. I hadn’t had a massage in ten months.

But Alexander was at his best when he was desperate. He communicated to his men that this was a gamble, and that the throne and empire were at stake – and that he took their trust for granted and that he needed them. He went from mess group to mess group every evening, which was unlike him – he wasn’t aloof, he listened when common men talked, and he made them promises – promises of rest when Greece was returned to obedience. And promises of loot I didn’t think we could fulfil.

We rose in the dark and we didn’t get to sleep until darkness fell again. In between, we marched.

Some days, I could look back from where I was near the lead of the column – mostly single file – and down a mountain valley I could see our army stretching back ten stades or more, filling every trail.

Villages emptied ahead of us.

That was just as well, because when we found a village, we looted it down to picked bones, and the bones were broken to get at the marrow.

And that will give you an idea of what it cost to go a hundred stades a day across the mountains.

We came out of the mountains in northern Thessaly. We raced across the Thessalian plain fast enough to shock every man we came across, but slowly enough to feed our horses to bursting on the good Thessalian grain – and grass – every day for four days. Our men ate beef and goat and lamb and bread – ate sausage even as they marched. Thessaly was friendly and had magazines and the king – who had no money at all – had credit there. We ate our way south.

I led the cavalry patrol that seized the Gates of Fire. I knew the way, knew the passes, and I was there and in possession – with a powerful sense that I’d done all this before – and there was no opposition. The grumblers in every regiment began to suggest we were attacking nothing.

We marched over the mountains to Onchestus and no one troubled us with so much as a sling stone.

And then we marched down on to the plains of Boeotia, the dance floor of Ares, and the race was run. The Athenians had not marched to the aid of Thebes, and Thebes did not have a Persian army camped under its sheltering walls.

That night, Alexander received letters from Pella, and a report that our siege train and most of our heavy baggage – including tents – was just five days behind us. Antipater had moved quickly, spending money Alexander didn’t have. In a few days, we were going to have twenty-six thousand soldiers.

Alexander dispatched heralds to Thebes. He sent them excellent terms – already, his mind was full of Asia. Or perhaps it always had been, but the spectre of Persian gold at Athens and Thebes brought home to him that Asia was not just waiting for conquest – Persia might, indeed, strike back at him. At every campfire across the Thessalian plain, he’d explained to us that he would be easy on the Thebans if they would bend the knee quickly, because he wanted to get fresh troops across the Bosporus before winter.

In his messages, he announced that he understood that they had been misled – and assuming him dead, had acted appropriately. He simply pointed out that he was not dead. He offered to meet a delegation and affirm the ancient liberties of the Polis.

The next morning, we marched early. Once again, I had the Prodromoi and the Hetaeroi, with orders to choose a camp – carefully, and with due respectfor Thebes.

Well, I had little respect for Thebes, but I knew what Alexander wanted. Despite which, I fanned the Prodromoi out fifteen stades either side of our approach road, and I put strong parties of Agrianians in a chain behind them and kept the Hetaeroi together as a strike force.

Just another routine day, marching through Greece.

Before noon, the Prodromoi officers were reporting near-combat contacts, and parties of Theban aristocratic horsemen who they flushed from cover – olive groves, mostly – with flanking moves and who rode away. Since they had restrictive rules of engagement – in effect, we’d been told not to engage unless the Thebans started it – the Prodromoi just manoeuvred them out of their ill-set ambushes and continued forward. But that sort of thing is exhausting and annoying work, and by late morning, I was being begged for permission to ‘make an example’.

I didn’t have to. The idiot Thebans did it for themselves. They came at us in mid-afternoon, four hundred cavalry emerging from behind the low hills north of the city to flush my Prodromoi back on the column.

The Prodromoi retreated in good order, very quickly, and broke contact. The Agrianians went to ground and the Thebans never, I think, knew they were there.

I had a long chain of reports, so that half an hour after the Theban attack started, I had all my Hetaeroi in two small wedges facing down a long field of barley, with a hundred Agrianians on each flank.

The Theban cavalry rode into the other end of the field, as I had expected. After all, I was getting a new report on their movements every five minutes.

‘Don’t even twitch,’ I said to my men. ‘Let them do it, if they want.’

They rode away.

We rode up to Thebes and I picked a campsite – the same site we’d used the last time. I felt that sent the right message.

Alexander must have agreed, because he gripped my hand at the end of the day. ‘Well done,’ he said. ‘They won’t fight now – but you left them no bodies to mourn. Well done.’

I loved his praise, when it was good praise.

I went to bed a happy man, and awoke to the sound of screams.

The Thebans had attacked our outposts in the dark – a huge attack, with twelve hundred hoplites. They came across the open ground in silence, and of course our army hadn’t fully entrenched, or anything like it. And Perdiccas hadn’t taken the precautions he should have. His outposts were surprised and overrun, and the Thebans killed at least two hundred pezhetaeroi and fifty hypaspists. And then they withdrew, untouched – we didn’t find a single body. Of course, they may have taken their dead with them – that’s certainly what I wrote in the Military Journal.

Either way, they hurt us and we did nothing in response, and that emboldened the war party. No matter that I’d shown them how toothless their cavalry was – never mind that we had every advantage. When men are determined on violence, it’s like a plague, and you cannot stop it.

Philip Longsword was among the dead. Alexander stood by his body in the new light of dawn, and he had white spots on either side of his nose and his lips looked pinched. His face was thinner than I’d ever seen it, and his ram’s horns were more pronounced. He looked like a satyr – a very angry satyr.

But despite that, he ordered our troops to dig in, and avoid combat contact.

So we did. The Hetaeroi, being aristocrats, didn’t dig – except in emergencies – but we were mounted in armour all day, moving from trouble spot to trouble spot.

The Assembly of Thebes voted for war to defend their liberties.

Our siege engines were three days’ march away. And our tents.

It rained. We were wet. Luckily, Greece is dry all summer, but autumn was coming.

The hypaspitoi marched out of camp and spread out, supported by the Agrianians, pillaging the countryside. This was an ancient tradition in Greek warfare. It was a public and somewhat formal statement – it showed the defenders that they could cower behind their walls, but they would lose everything outside them.

We understood from men inside the walls – because many Thebans were supporters of Alexander – that the Assembly was now divided. So, after some hesitation, Alexander had his heralds proclaim at the edge of the walls that any Theban who wished to come out of the city would be allowed to go free – or that if Thebes surrendered the two men who had murdered Macedonians, it could still avoid war. His herald reminded them that Alexander was the hegemon of the League and that Thebes was in violation of her sworn oaths.