‘Is this the Zuiderzee?’ I asked.

Captain Thoms laughed. ‘Not this. No, this is the Haarlemmermeer, one of the most treacherous areas in the Low Countries.’

‘Treacherous!’

‘More treacherous to the people who dwell round its margins than to us. It is a victim of what they call the “wolfwater”, the water which rises in these low-lying inland lakes – fast, unpredictable – and devours whole villages.’

I shivered. ‘But not treacherous for us?’

‘Treacherous enough. We must pick our way through it, where the water is deep enough. Shifting mudbanks here, not sandbanks. Easy enough for us to become stranded.’

He walked away to supervise the lowering of the sails. We would have to make our way again under oars. The wide marshland seemed almost deserted, except by birds, for there were flocks of ducks and moorhens, solitary herons standing in the shallows like sentinels, a flight of gulls screaming raucously overhead. The very smell of the place was different, a reek of mud and rotting vegetation. Over on the eastern edge of the deceptively quiet waters I saw a few small fishing boats, and beyond them smoke rising from a cluster of cottages. Otherwise, desolation.

At length we came to the end of the Haarlemmermeer, passing through a short canal into what the captain said was the Oude Meer. The sails were hoisted again and the ship picked up more speed, heading northeast.

‘We are nearly at the Zuiderzee now,’ Captain Thoms said.

Even as he was speaking I could see the wider waters ahead and soon we had sailed out on to what seemed to be a vast inland lake, though Thoms assured us it was salt. The ship came about and veered to starboard. The foresail was lowered, and then the mainsail, so that we made our way more slowly under staysail alone. Captain Thoms climbed out on to the base of the bowsprit, holding on to the rigging with one hand and leaning far out over the water, swinging the lead himself. As he checked the lead line, he signalled to the steersman to guide the ship first to port and then to starboard, to avoid the sandbanks.

I was so absorbed in watching him that it was only when Berden tapped my arm that I looked up and saw the buildings of Amsterdam drawing near. There were ships everywhere, some clearly warships, some merchant vessels, while dodging in amongst them were round-bellied fishing boats, small pinnaces, and open rowing boats. Satisfied that he had found the main channel into the town, Captain Thoms climbed back on to the deck, nodded to us as he passed, then gave the order to lower the staysail and run out the oars.

As the Silver Swan was brought neatly in, between the anchored and moored vessels, I could appreciate the captain’s skill. He had found a space beside the quay and himself took over the steering to lay the ship alongside without a bump. While the sailors were busy mooring the ship and running out the ramp, Berden and I saddled the horses and strapped on our luggage. This time I led the way across the ramp on to the quay, Hector following me with blithe unconcern. Berden had not put the blinkers on Redknoll and when the chestnut saw how calmly Hector crossed the ramp, he followed us, after only a slight hesitation. The captain stepped ashore behind us.

‘Our thanks to you, Captain Thoms,’ Berden said, shaking his hand. ‘We will hope to see you here in three weeks’ time.’

‘Aye, unless the canal ices over. If it does, I will meet you where we moored last night.’

‘Thank you, Captain.’ I shook his hand in my turn. ‘It was a rough crossing, as you predicted, but you brought us here safely.’

‘I hope it will not be worse on our return,’ he said with a smile. ‘In three weeks, then.’

He turned to go back on board ship, where the sailors were already dismantling the stable. Then he glanced back over his shoulder.

‘I will see about the scurvy grass while I am back in England, Doctor.’

I raised a hand in acknowledgement, then we led our horses off the quay and into the busy crowds of the port. There was a Babel of voices around us, in which I could pick out French, Spanish and Italian as well as English, though the majority were speaking an unknown language which I supposed must be Dutch. Although it was unknown to me, somehow I almost felt I could understand it, for its rise and fall closely resembled English and even scattered words sounded like English.

Berden appeared to know where to go, for once we had mounted our horses he headed off confidently along a narrow cobbled street beside a waterway which might have been a river or a canal. I could not be sure. I knew that the town, like Venice, was built on a cluster of small islets of slightly higher ground rising up in the middle of a bog, but thanks to the skill of the Dutch engineers, more and more land was being reclaimed. At the moment the plan of the city was confusing and already dusk was falling.

‘How can you find your way in this place?’ I said.

‘I’ve spent some time here,’ Berden answered, speaking over his shoulder, for it was too narrow for us to ride abreast. ‘There is talk that someday they will rebuild the town, or at least straighten out some of the meandering waterways.’ This as we rode over yet another hump-backed bridge. ‘But the town will need to become a good deal richer, and the Hollanders free of the Spanish, before they can undertake so large a building project.’

We crossed an open square with a public well in the middle and turned into a wider street, so that I was able to bring Hector up beside him.

‘Nicholas, before we see the Earl – is he to be told what our real mission is, here in the Low Countries, besides carrying despatches?’

‘No,’ he said, ‘Sir Francis has decided we should behave as if we were nothing more than messengers. It is not that he does not trust the Earl, for they have been close friends for many years, but sometimes the Earl is a little careless in his talk. And the loyalty of some of those about him on these foreign shores may be doubtful. Remember, there have been English traitors who have deserted to Spain. And recently things have become strained between the Earl and the Dutch leaders. Although he is no longer called Governor General, they find many of his actions high-handed. He is a poor diplomat and does not consult them as he should. If there is a traitor close to the Earl’s own person, such a man might catch a whisper of our mission, or even guess from the way the Earl conducts himself towards us. Our wisest course is discretion.’

‘Good,’ I said. ‘That seems best to me too. Though knowing that we work for Walsingham, and knowing what he wrote to the Queen in his recent letter, the Earl may himself guess why we have come.’

‘That is a risk, of course,’ Berden conceded, ‘that we must take. Here, this is the house where the Earl and his immediate entourage are lodging.’

I looked where he pointed. The house was built in what I was coming to recognise as a typical Dutch style as we rode through Amsterdam. It was tall. Four regular storeys with an attic storey above, behind the characteristic fluted gable high above the street. Most of the houses had an opening here, much like the hatch in an English hay barn, through which the hay can pitched down, except that here there was usually a hoist extending out over the street. The houses, I assumed, must also serve as places of business for the merchants of Amsterdam. The house Berden pointed out had the opening in the high gable end, but there was no hoist and the opening was shuttered. Three shallow steps led up to the front door and there was an archway to the left which appeared to lead through to outbuildings or a garden to the rear of the building.

We dismounted and secured our horses to tethering rings set into the front wall of the house. By the time I had slung my satchel over my shoulder and Berden had removed his wallet of papers from his pack, the door was opened by a serving man in the Earl’s livery. Someone must have been watching from a window.