Our ships returned to their ports once the Armada had vanished into the north, but hidden behind the general rejoicing a grim shadow lurked. The men of our fleet had sustained the usual battle injuries, but the gods of war had laid a different curse on the victorious soldiers and sailors. A man would come ashore from his ship, join his friends for a drink at an inn, then collapse in the street and die within hours. There was no warning. No visible symptoms marked out those who were doomed from those who were untouched. Two men might share the same meals, fall asleep in adjacent hammocks. In the morning one would wake, the other lie stiff and cold. Whispers of witchcraft ran darkly through the streets. Others saw the hand of God in this. Had we become too arrogant in our victory? Or – whispered amongst those who still inclined to the old faith – was the Pope’s blessing upon the Spanish attack bringing down on us a righteous punishment? Witchcraft, retribution or natural disaster, the outcome was the same. Men were dying, and dying in large numbers.

The morning after a number of the ships were reported to have berthed at Deptford, my father received a message from the authorities at St Bartholomew’s.

‘You must pack your satchel, Kit,’ he said. ‘We are sent to Deptford to treat the sickness which is spreading amongst the men. Bring all we have of febrifuge medicines and tincture of poppy for the relief of pain.’

He was packing his own satchel as he spoke.

‘What are the symptoms?’ I asked, as I secured cork stoppers with wax and then wrapped the glass bottles in rags for safety.

He shook his head.

‘From all I have heard, no one can be sure. Only that those afflicted are seized with raging fever as if they would catch on fire, and the pains they suffer are acute, so severe that some have leapt into the river to seek death, as the only way to escape.’

I shuddered. ‘I heard that some have simply been found dead and cold in their beds, with no sign of illness at all.’

He nodded. ‘Whether these are two different forms of the sickness, or two completely different afflictions, who can tell? It cannot be the plague, for there are no marks of the plague on them.’

That was one hopeful sign, for the plague could sweep through London in days, mowing down all before it.

‘And it is only the men from our fleet who are affected?’

‘Aye. Sailors and soldiers both.’

‘Gentlemen and officers as well?’

‘I have not heard so.’

‘Could it have come from the common men’s food?’

‘Perhaps. Yes, that’s well thought of, Kit. It might be wise to take vomitories and enemas as well. Though I have not heard that there have been signs of food poisoning.’

I reached down the additional medicines from the cupboard. If it was food poisoning, surely all of the men would have been seized with the illness. Still, best to be prepared.

He took out a handkerchief and mopped his face. ‘Are you ready?’

I nodded and shouldered my satchel. We left Joan instructions for the next few days, not knowing when we might return, and I warned that I would expect Rikki to be fed and cared for. If he was not, she should answer for it. We turned our backs on our house and made our way down to the river.

The summer heat had continued stifling in Duck Lane and on the wherry the slight breeze over the river brought welcome relief. My father wiped his face again.

‘Are you well, Father?’

He did his best to smile. ‘I find the heat more trying as I grow older. I will soon feel better in this cooler air.’

I frowned. I had never known him mind the heat before. Indeed England’s weather was far milder than the summer’s heat we had left behind in Portugal. He was more apt to complain of the cold in an English winter. Whatever was afflicting the men at Deptford, I hoped it would not be infectious, for my father did not look well.

All too soon the trip down river was over and we found ourselves amongst the ships moored five or six abreast along the quayside. The quays themselves were eerily deserted and at first we could find no officer, but at last an elderly man in clerical dress, disembarking from the nearest ship, directed us to a small building, hardly more than a shed, where we found a harassed-looking junior officer who appeared to be the only person in charge.

‘Physicians from St Bartholomew’s? The Lord be praised,’ he said. He had removed his ruff which lay, grubby and creased, on a table amongst a pile of documents. He has loosened his shirt strings and his hair was unkempt as a neglected birds’ nest. He looked as though he had not slept for many nights.

‘Not that there is much you can do,’ he said. ‘They are dying almost before we know they are sick. Even on the few ships still patrolling the coast, in case of further attack, men are dying. Every day we have word of men buried at sea. With these crews berthed here at Deptford I am trying to send as many home as can walk.’

He gestured towards the documents. Discharge papers, I guessed.

‘But some of those who are well will not leave until they are paid, and no pay has come for them yet.’

‘What? They defeated the Spaniards, but they have not been paid?’ My father was incredulous.

The man shrugged. He looked at though it did not surprise him. ‘Quarrels amongst those who must find the coin, I suppose,’ he said. ‘No one gave thought to pay when we were mustering for war.’

‘But if you send sick men out into the country,’ I objected, ‘you may spread this disease even further. It could ravage every village and town in England.’

He shrugged again. ‘I cannot help that. We cannot feed them and I’ve been ordered to dismiss them.’

It sounded as though these men were being treated as mere parcels of inanimate goods. They had served their purpose, and now there was no more need of them.

‘Where are they, the sick men?’ my father asked.

‘Sick and well, they’re still on board the ships. We have nowhere else to put them.’

And so began our grim task of treating the heroes of the Armada. The sick men were lodged in hammocks strung between the cannon on the gun decks; those not yet struck down squatted anywhere they could find space, playing cards, dicing or throwing the knucklebones.

It quickly became clear that we were dealing with two illnesses. It addition to the mysterious affliction, there were many obvious cases of the bloody flux.

‘The wisest course,’ my father said, ‘would be to separate the cases.’ He looked about him in despair at the men all crowded together, sick hugger-mugger with well. His shoulders sagged defeatedly. We were standing on the gundeck of a large warship, a galleon carrying forty demi-culverins.

‘I’ll talk to the men who are yet unaffected,’ I said.

For years I had followed my father, taking my lead from him, but I realised now that I must act for myself. My father was simply too tired to confront what seemed a task far beyond our capabilities. I had noticed a big man of middle years to whom the others seemed in some ways to defer. He had a broad, sensible countenance and a quiet manner. I asked his name.

‘Tom Barley at your service, Doctor.’ He gave me the ghost of a smile. ‘Not that there is much service I can do you.’

‘That is where you are wrong,’ I said. ‘We need to separate the men. Move those with the flux aside to separate them from those with this other sickness. And I want the men who are well kept away from those who are sick.’

‘There’s nowhere else for us to go, Master.’

‘Why not up on deck? It’s summer weather. It’s cooler up there and you will be in less danger of the sickness. Is there spare canvas? You could rig up a shelter to protect you from the sun.’

He grinned. ‘The officers won’t allow that. This is where we must stay. Orders.’

‘There are no officers,’ I said bluntly. ‘They have taken themselves off.’