Age of Invention: Salt Syndicate, Part I

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It’s been a while since my last post, but I hope this will be worth the wait. Regular readers—patient readers—will recall that a couple of years ago I had a few posts about the economic history of salt. I described how the lack of salt in the Baltic had given rise to the Hanseatic League, and how the Dutch had then supplanted them in that trade, such that salt became the principal economic pillar of the Dutch Republic’s Golden Age.

Patient readers may also, however, remember that this was not supposed to be the end of that series—that there was to be another chapter, on how the Dutch dominance of salt came to be replaced by British coal.

I had already done a great deal of research for that next chapter two years ago. In a way, the entire salt series had just been building up to it. But as I began to write up the main event, so to speak, the unanswered questions began to mount. For every loose end that I pulled on, three or four of the stitches I had already written up would come loose, leaving me with just an unsatisfying tangle, more plot-hole than substance. So I left it simmering away in the background for a couple of years, occasionally stumbling across a few bits of additional evidence while looking for other things. Until, a few months ago, one of those stumbles yielded a major breakthrough, extirpating a few red herrings and leading me to embark on a months-long, desperate search of archives all over Europe—in Britain, Belgium, the Netherlands, Germany, Italy, Denmark, and Sweden, sometimes in person, sometimes thanks to the diligence of archivists and the kindness of volunteers, so that I could finally write it up.

What follows is the story of possibly one of the most important inventions of the sixteenth century that hardly anybody has ever heard of. It is still a work in progress; I have no doubt that there are some missing pieces just sat there waiting in an archive, overlooked for centuries. But by putting all I’ve found so far together, I’m hoping that it will inspire readers to join the search, or at the very least allow historians who stumble across a missing piece to immediately recognise it for what it is.

The reason for the story’s complexity, and the reason I think it has for so long been overlooked, is because of a phenomenon that has not really been noticed before: that what may appear, at first glance, to be entirely disconnected improvements to the same industry across various different countries, is often revealed by the letters they wrote to one another to actually all be a concerted effort to promote a single invention across multiple jurisdictions. In other words, many major inventions—not just techniques known in one place and absent in another, but discoveries new to everywhere—were promoted and patented across as much of Europe as possible via multi-national syndicates.

I described one such unsung syndicate last year: the one that promoted the 1550s invention of a new kind of oven to save wood fuel, called the holzersparungs kunst, or wood-saving art, which was to have an inadvertent but dramatic effect on the rise of British brewing and coal. But I only found out about that syndicate because I had been researching another one, which had been promoting a new method of making salt with less fuel—an invention that was taken far more seriously at the time.

As we shall see, this saltmaking invention was to spread over the course of the 1560s from the Atlantic to the Urals, and from the Mediterranean to the Arctic, eagerly adopted by rulers all over Europe who saw in it the potential to free themselves from the mercy of foreign powers. Just as control of salt had been the basis of empires, the ability to make salt locally promised a means of liberation. No mere minor improvement, the invention was treated as a breakthrough of major strategic significance.

So what was it, and what impact did it have? The answer to that is long. Very long. So get yourself a caffeinated drink, or perhaps something stronger, and settle in to read the untold story, not just of an invention, but of high political intrigue.

The Evaporational Arts

The story of the salt-making invention began in the minds of two Germans obsessed with metals. One was Berthold von Holzschuher, a Nuremberg patrician in his late forties, who descended from one of the city’s great ancient dynasties. Nuremberg was famed for its copper and brass industries, and Holzschuher had interests in copper-smelting, marrying the daughter of Jakob Welser, a wealthy banker from Augsburg who came to control the Nuremberg’s copper supply. Yet he was also a serial inventor, not only in metallurgy, but in the design of intricate mills and fantastical war machines. In 1558 he drew up a remarkable will, bequeathing detailed plans of his most secret devices—considered, by some historians, to be the first modern blueprints drawn entirely to scale.

The other German, Holzschuher’s collaborator, was a metallurgist named Caspar Seeler, based at Augsburg—the nerve centre of German finance. Many of the basic details of Seeler’s life are obscure; I’ve not yet even been able to find when or where he was born or died.¹ He first pops up in the records in the 1550s as a financial agent for the prince-bishop of Würzburg, minting his coin, lending him money, and negotiating loans from other Augsburg-based lenders too. He also, however, appears to have invented a mill-powered machine to automate various aspects of the process of making coin. His invention may have been the machine sold at Augsburg to the French in 1550, and investigated by the Spanish, which reportedly allowed a single boy of fifteen to produce as many coin blanks in a day as fifty men could cut by hand.² Certainly, in 1555 Seeler was in negotiations with the Habsburg archduke of Austria, Ferdinand I, to install a newly invented machine at the Austrian mint at Hall, in Tirol, and he was also eventually voted a large advance by the diet of the Holy Roman Empire—what was, in effect, its parliament—to install one for minting imperial coin. In 1556 Seeler was also appointed the master, at Augsburg, of the imperial mint.³

Yet just as his minting machine was being adopted, Seeler and Holzschuher were also working together on what they felt was the more momentous device: their invention for saving fuel in the making of salt.

Wood fuel was by far and away the biggest constraint on salt production in inland Germany. Decades later, for example, when the salt springs at Reichenhall wanted to expand production, the brine needed to be piped for 30 kilometres, and pumped over a mountain in seven stages, to a height of 300m, just so that it could be brought to a forest with sufficient wood fuel to evaporate the water and extract its salt.⁴ Any way to save fuel when making salt in inland Germany was a major boon to an economy already straining every sinew to support its population at a tolerable standard of living. It freed up forest to fuel other industries, or allowed the land to be repurposed, the forests cut down and the land ploughed up for growing more grain. It also allowed the inland areas where the known salt springs were too weak to bother spending any fuel evaporating them—areas that were thus at the mercy of their more salt-rich neighbours—to be able to finally free themselves from their costly dependence.

We do not know precisely how Holzschuher and Seeler’s earlier prototypes worked, but we do know the basic underlying principle: before any fuel was burnt, they first tried to encourage as much ordinary evaporation as possible by increasing the surface area of the brine, allowing the wind to do its work more rapidly. The more they could evaporate this way, the less fuel would be needed to remove the water that remained.

Annoyingly, the many plans and descriptions of how it worked at first—often alluded to in the sources—have proved impossible to find despite my many months of searching. Perhaps they have not survived at all, though the sheer volume of material about the invention across so many different countries’ archives leads me to hold out hope. But from a scattering of hints it sounds as though at the beginning the invention consisted of a kind of waterwheel covered with reeds or straw, which rotated in a reservoir of collected brine. As the brine adhered to the straw and dripped from it with every rotation, it was split into a multitude of tiny droplets exposed to the air, vastly increasing the liquid’s surface area and accelerating its evaporation. The brine, worked by the straw-covered wheel for over a week, could then be passed through a series of shallow pools for further evaporation before being heated in pans and refined. The exploitation of the principle came to be known as a luftgradierung, or air-graduation process.⁵

In 1558, Holzschuher obtained a patent monopoly for the invention covering the Holy Roman Empire, and then the partners got to work trying to get their luftgradierung adopted.⁶ Starting locally, in 1559 they offered it to the duke of Bavaria for the saltworks at Bad Reichenhall, but another opportunity intervened, for in the autumn of 1560 Seeler was in London. Bearing letters of introduction from his old employer, the prince-bishop of Würzburg, who called him “outstandingly and eminently versed and experienced in monetary and metallurgical matters”,⁷ Seeler went to England as part of a German partnership hired by Elizabeth I to undertake the recoinage of the currency: a vast operation by which the copper and brass in all of the heavily debased silver coins in circulation were extracted, cheaply and quickly, so that they could then be re-minted and reissued at a higher fineness. Soon, Holtzschuher and some fifty other expert German metallurgists were to join him there too.⁸

Despite this diversion, the recoinage gave the partners crucial introductions to the merchants and politicians of both London and Antwerp, where their contract had been negotiated—contacts that they could now lean upon to promote the luftgradierung. Over the course of 1562 they not only installed the first operational version of it close to home, at the Kissingen saltworks belonging to the bishop of Würzburg, but they obtained a 20-year patent monopoly in the Habsburg-ruled Low Countries (the area today roughly corresponding to modern-day Belgium and the Netherlands).⁹ This is where the scale of the invention’s promise began to become clear.

Going Dutch

The commercial opportunity in the Low Countries was vast. The Dutch imported huge quantities of coarse salt, half of it from the southwestern coast of Spain and from Setúbal in Portugal, and the other half from France’s western coast along the Bay of Biscay, all of which collectively came to be known as “bay salt”. Made from the sun and wind slowly evaporating the seawater of the Atlantic in a series of shallow coastal pools, bay salt formed in coarse, large-grained pieces that were skimmed off the top. Never filtered, and often mixing slightly with some of the sand and dirt from the bottoms of the pools, bay salt was often brown, green, grey, or black, as well as containing the many other chemicals found in seawater, like magnesium chloride and sulphate, calcium carbonate and sulphate, potassium chloride and so on, known as bitterns.

Although bay salt was useful for preserving food, and above all cheap, it had its limitations. It was unsuitable for preserving dairy, its dirt discolouring and adulterating the butter and cheese. It often left meat or fish still rotten on the inside, because its large grains meant that it dissolved both slowly and unevenly, its bitterns also slowing the rate at which it started to penetrate and preserve the flesh. And the bitterns gave flesh a bitter, gall taste, affecting its texture as well. Meat and fish preserved with bay salt was often shrunken, hard, and tough.

The Dutch re-exported huge quantities of bay salt to the Baltic, Britain, and Scandinavia, for use in their meat and fish industries. But for the industries of the Low Countries itself, they refined it. Dissolving the imported bay salt in some water in a pan, they used their plentiful supplies of peat to boil it, removing much of the dirt and adding egg whites and a bit of ox blood to remove the bitterns as well. The resulting refined salt, often known as “salt upon salt”, was both pure and white. Peat-fired white salt was the foundation of Dutch wealth: the key ingredient for preserving butter, cheese, and above all herring, giving them an unassailable edge over every other competitor.

Huge Dutch ships, the herring busses, went far out into the North Sea beyond Scotland to the Shetlands and Orkneys, carrying with them the workers, barrels, and refined white salt to immediately gut and pack the herring while still out at sea, with a fleet of smaller supporting boats continually shuttling supplies from the coast. Of approximately 600,000 barrels of refined white salt being produced in the Low Countries each year, just under a quarter of it was consumed by the herring industry alone.¹⁰ Dutch-caught herring was exported all over the Europe for various luxuries, but especially to the relatively salt-less Baltic for the essentials, buying timber for building the fishing ships, the pitch to caulk them, the hemp for their rope and rigging, as well as the grain to feed the Low Countries’ burgeoning cities. The wonder of the age was that a small country so devoid of trees or rich farmland could have its ports packed with ships and its granaries overflowing with grain.

But if the salt trade was already the basis of extraordinary and growing Dutch wealth, the luftgradierung promised to make it wealthier still. What Seeler and Holzschuher promised in 1562 was a way to free the Low Countries entirely of its dependence on the salt of France, Portugal, and Spain, instead extracting it directly from the saltwater of the North Sea. For close to half of the previous fifty years, the Low Countries had been embroiled in on-and-off wars against France, which in 1562 also descended into what would prove the first of many religious civil wars.

The conflicts frequently disrupted supplies of bay salt from France itself, which was the closest and cheapest source it, as well as increasing the prices of salt from more distant and expensive Iberia, the ships carrying it having to pass by the entirety of France’s western and northern coasts, travelling in large armed convoys to avoid becoming prey to French warships and privateers. The price of bay salt, and thus of the white salt made from it, could often spike within a matter of months by 30, 40, or even 100%.¹¹ To make matters worse, even during peacetime the French king profited directly from the sale of his country’s salt, so that Dutch imports of it simply built up his funds for fighting the next war.

What the luftgradierung promised, then, was for the Low Countries to no longer have to import bay salt from France or Iberia, to simultaneously allow its exports of herring to be made even more cheaply, and so to enable that herring to purchase more exciting imported luxuries instead. Not only would the Low Countries be further enriched and become more self-sufficient in the making of its chief source of wealth, but the French would be weakened, making the disruption to trade from French invasion less likely. And if that were not already attractive enough, the constantly cash-strapped ruler of the Low Countries—the Spanish Habsburg emperor Philip II—might also obtain a whole new source of revenue as well.

Philip II and his father before him had not only been forced for decades to fight France on the borders of Italy, Spain and the Low Countries, but had also been locked in a long war against the Ottoman Empire along the coasts of Italy, Spain and North Africa. In early 1560, a vast Habsburg-led Spanish-Italian armada captured the island of Djerba off the coast of Tunisia, only to lose both fleet and fortress within months. The Ottomans had been left in command of the seas, menacing Spanish strongholds in North Africa, raiding the coasts of Christendom with impunity, and even blockading the largest city of Philip’s empire, Naples.¹²

And although the descent of France into religious strife had provided the respite needed to take on the Ottomans, it seemed only a matter of time before it bounced back. Indeed, over the course of the 1560s and into the early 1570s it would seem more threatening than ever. We now know, with the benefit of hindsight, that there would be no further outright war between the Low Countries and France for many decades to come, but that was not how it seemed at the time. To Philip, who believed his divinely-appointed mission was to bring about the worldwide victory of Roman Catholicism, the proliferation of Protestantism in France was a gangrenous sore infecting the souls and corrupting the loyalty of his subjects in the Low Countries. 5,000 French Protestant soldiers were even to cross into the Low Countries in support of their co-religionists in 1572. Should the Protestants win outright in France, he would have a heretical great power on his borders, ever interested in aiding religious rebels. And even though the religious strife wore on, the French king Charles IX became increasingly convinced that the only way to re-unite his subjects was to provide them with a common enemy by invading the Low Countries.

Philip needed lots of cash—and quickly—if he was to face these looming threats.

By the time Seeler and Holzschuher arrived on the scene in 1562, Philip II had already been urgently considering how better to tap the growing wealth of the Low Countries—his wealthiest dominion by far. The problem was that Habsburg control over the region had been established in a piecemeal fashion, with newly conquered territories given major concessions to keep them loyal and happy, and with many of those privileges closely guarded, preventing them from being taxed more. The representative bodies of the various provinces of the Low Countries—the Estates—were reluctant to vote him sums for the various Habsburg war efforts, and had to get unanimous agreement from their constituent cities even when they did. Persuading them to part with one-off sums was hard enough, let alone attempting to increase revenues permanently, and in the meantime Philip was plunged ever more into debt.

What Philip needed was a clever workaround that would both raise revenues and make his subjects better off—a possibility potentially offered by salt. In 1559, an Italian entrepreneur Giovanni Leonardo di Benevento had suggested that the government simply monopolise all salt-refining, which he promised could both yield a profit and result in lower prices. This was flatly rejected by the Estates. Undeterred, Benevento and one Stefano Ambrosio Schiappalaria were in 1562 given the go-ahead from the government to try and simply buy out all of the 400 salt-refining pans in the country using private capital. If they could achieve the monopoly through voluntary agreements, then they could simply bypass the Estates entirely without impinging on any ancient rights. But they only managed to take over the pans in Zeeland, with the negotiations breaking down with the refiners of all of the other coastal provinces.¹³

And then Seeler and Holzschuher appeared on the scene with their entirely new and supposedly cheaper means of making salt—one that might simply undercut and drive out of business all of the remaining salt refiners, and which as a new invention could legally be granted a temporary monopoly patent directly by the king, without any say-so from the Estates. Although the importers and refiners of bay salt would suffer, it was otherwise a win-win: the people of the Low Countries would benefit from a cheaper and more reliable source of salt, and the king would be able to monopolise the entire country’s salt industry through the power of competition.

This potential was not seized upon immediately. The original patent in the Low Countries in October 1562 over-optimistically only covered salt made from seawater using the luftgradierung process alone, without allowing the use of any fuel at all. Perhaps Seeler and Holzschuher had over-estimated what their invention could achieve, but it’s also possible that this was the maximum extent that the government had been willing to grant to a project competing with its Benevento-Schiappalaria scheme. As the failure of that scheme became clear, however, the patent for the luftgradierung was re-negotiated, with Philip’s government becoming a lot more closely interested in its success. In February 1563 the patent was re-issued to cover any use of the process with or without fuel, but with the king taking a 25% cut of all the white salt produced, and with the entire business coming into his ownership when the patent expired in 19 years’ time. Seeler and Holzschuher were now effectively setting up a nationalised industry in waiting.

But what is most interesting of all is that the terms of their agreement extended to other countries as well. Their existing monopoly in the Holy Roman Empire would be unaffected, as it was largely only applicable to inland salt springs. But Philip’s government placed major restrictions on what Seeler and Holzschuher would be able to do in any countries with a coastline—those that might compete with the Low Countries by producing white salt from seawater as well. The partners were allowed to patent in those countries—the agreement listed England, Scotland, Denmark, Sweden, Emden, and the Hanseatic cities of the Baltic as the most likely candidates—and in fact appear to have been encouraged to do so, as this would the best way to prevent the technique being pirated by rivals. The idea was that by obtaining patent monopolies in those countries as well, Seeler and Holzschuher would be able to control all potential competition with the Low Countries, preventing Philip’s profits from the monopoly being undercut. To ensure that Philip always came first, they even agreed to pay him a 1% royalty of all the salt they produced from seawater worldwide.¹⁴

What Seeler and Holzschuher signed in February 1563 may well have been the first ever contract to cover intellectual property rights globally. The only problem was that obtaining a monopoly on the process in all those competing jurisdictions—and persuading foreign rulers to go along with Philip’s priorities—was easier said than done.

The Malicious Mr Berti

Seeler and Holzschuher both had a great deal of technical expertise between them, and had developed many international contacts of their own. But if they were to obtain monopolies in all the competing courts of northern Europe quickly, they needed someone who was footloose in the extreme—someone known in every quarter, with friends by every throne. They needed Francesco Berti.

Born to a Florentine merchant dynasty in Antwerp, Berti had likely traded with England too, and been attracted to English service because he was a Protestant. In the pay of the English crown since 1546,¹⁵ presumably as a spy, in 1550 he was instrumental in founding a church in London for religious refugees from Germany and the Low Countries,¹⁶ and was naturalised as an English subject the following year. Ever on the move for trade, he was a familiar face at the courts and markets of France,¹⁷ Germany, and Sweden,¹⁸ and probably elsewhere as well. A natural schemer, Berti was described by a Habsburg spy in England as “a man exceedingly cunning, sharp, double-dealing, avaricious, and malicious, if ever there was one in the world”—all of which made him immensely useful to a lot of powerful friends.¹⁹

Just as Berti became involved in promoting the luftgradierung for Seeler and Holzschuher, he was also involved in a dangerous scheme to determine the marriage of England’s queen, Elizabeth I. Berti was close to Elizabeth’s favourite, the dashing Lord Robert Dudley, younger brother of the earl of Warwick. Dudley hoped to marry the queen, and at certain points in the early 1560s it looked likely. He had substantial faction at court behind him, helping to make his case. But to be in with a realistic chance, he also needed to see off the most diplomatically advantageous and annoyingly persistent rival for her hand, the king of Sweden Erik XIV.

Twice, in 1560 and 1561, Erik had tried to sail to England to woo the queen. Twice, he had been forced back by bad weather. In the summer of 1562, with his chancellor Nils Gyllenstierna and a faction at the English court egging him on, he planned to make the trip again. The pro-Swedish faction believed that Erik was sufficiently attractive to win the queen around should he appear in person, and even if Dudley was confident in his own charms, he at the very least feared how painfully awkward it would be for Elizabeth to turn down a reigning king who had come all that way and at no small risk of shipwreck or capture by pirates or enemies. Should Erik get to England, Dudley must have feared that diplomatic worries would end up carrying the day. The longer he could delay Erik’s trip, the more time he would have to root out his pro-Swedish opponents at court; if he could stop him departing altogether, then all the better.

So Dudley sent Berti to do his dirty work. They had known each other a long time, though it’s unclear exactly how long. In the 1550s Berti had lent money to Dudley’s mother, the duchess of Northumberland, and was to lend large sums to him too, as well as procuring him all sorts of luxuries from abroad.²⁰ Unfortunately, we also don’t know the full extent of Berti’s earlier intrigues in Dudley’s service, but whatever they were, they must have annoyed the Swedes greatly: even before the possibility of Erik’s trip, Gyllenstierna had already come to hate and fear Berti during his time as ambassador in England.²¹ If I were to hazard a guess based on some hints in the sources, Berti had been among the wealthy merchants in England who had extended credit to Gyllenstierna to support his embassy, but had then used his power as a creditor to harass him.²² Regardless, what we do know is what Berti was up to in the summer of 1562, because just as Gyllenstierna was about to leave for England to prepare the way for Erik’s third attempt, he was suddenly recalled.

According to a flurry of diplomatic intelligence and letters of complaint, Berti had arrived in Sweden bearing shocking information for the king. Elizabeth, said Berti, was lame in one foot, barren, and by no means a virgin. She had slept with Edward Courtenay, the earl of Devon,²³ who had died six years previously, and was still, he claimed, “a whore, giving herself to the said Lord Robert [Dudley], who lay with her every day as a husband with his wife, and that he ought therefore to think no more of the said marriage, since it was not fitting the king should have another man’s leavings”.

Such claims were so shocking, and so dangerous for Berti to have even voiced, that Erik cannot have failed to take them seriously—it seemed the kind of radical honesty that only someone who truly had his best interests at heart could make. It certainly put a stop to any serious attempt to win Elizabeth’s hand. Yet such doubts alone would not have been enough to halt Gyllenstierna in his tracks and force his embassy to be recalled. For that, Berti left Sweden—where Gyllenstierna could have got his hands on him—and from the relative safety of Germany he put about a rumour that ingeniously took advantage of Gyllenstierna’s debts in England.

Gyllenstierna had intended to repay the huge debts he had racked up on his previous visit, so had been about to leave Sweden for his embassy carrying a great deal of silver. But Berti rumoured that he had fiddled his expenses, and that he didn’t owe even half the amount he’d told the king. Gyllenstierna was, Berti claimed, going to use the silver to bribe his way into marrying one of the duchess of Somerset’s daughters, and so to flee Sweden forever.²⁴ And just for good measure, Berti added that Gyllenstierna had often claimed in London that he had a better claim to the Swedish crown than Erik did. Naturally, these rumours made their way back to Erik so swiftly that they got Gyllenstierna hurriedly recalled.²⁵ And so Dudley was given the free hand he needed back in London to root out and neutralise the pro-Swedish faction once and for all.²⁶

Once he’d managed to prove his innocence to Erik, Gyllenstierna reacted furiously. Writing to Elizabeth and her ministers with evidence of Berti’s double-dealings, he sought to see the slanders against him revenged. But, scandalously, Berti escaped all punishment. A gobsmacked Habsburg spy in England reported that only a mere “show was made of searching for him at his house”, even though everyone knew that Berti was in fact at court the whole time, staying in the suite of the queen’s female favourite, the marchioness of Northampton, Elisabeth Parr. Berti was allowed to quietly slip away to Antwerp until the diplomatic heat had died down, granted a licence to take a huge amount of money with him, and essentially given official protection. When Gyllenstierna sent his friends to petition for the seizure of Berti’s assets in England as compensation for his slanders, they were stonily told by two of the highest-ranking noblemen and government ministers to drop the suit.²⁷ The implication was shocking: although she could always plausibly deny it, Elizabeth herself must have been in on Berti’s intrigues too.

While all this was going on, Berti must also have entered into a partnership with Seeler and Holzschuher; for just a month or so after he had slipped away to Antwerp, his name was to appear alongside Seeler’s on their Low Countries monopoly patent, and he was soon raising capital and negotiating patents for them in both England and Scotland as well.

Florentines and the Machine

Berti’s readiest investors were merchants with backgrounds very similar to his own, having a foot in both Antwerp and London, and often a connection to Italy as well. There was Pierre de Roeux, presumably from the Roeux just east of Arras, now in France but then in the Low Countries, who had financial interests in London and had stood surety for Seeler and the other Germans when they came to England for the recoinage. There was the Genoese merchant Benedetto Spinola, who like Berti had been naturalised as an English subject in the early 1550s. And there were Berti’s fellow Florentines: the brothers Guido and Stiatta Cavalcanti, who had first come to London with their father Giovanni when they were children, and had then become major lenders to the English crown as well as suppliers of various luxuries from to its court.²⁸ Curiously, each of them was also suspected by a Habsburg spy of passing intelligence to England on what was happening in Europe—particularly to Elizabeth I’s chief minister, William Cecil.²⁹

Given the many close connections that both the German and Italian partners had with England, it was inevitable that the luftgradierung would be patented there. Indeed, Cecil wrote directly to Seeler in March 1563 calling him his “my very dear friend” and urging him to come to England as soon as possible to put the invention into practice. He said he had negotiated with Seeler’s attorney in England—one Thomas Heneage, a courtier and close friend of Cecil’s—and the monopoly was assured.³⁰ All Seeler had to do was come to England in person to sign on the dotted line.

Cecil was ever anxious when granting a patent that the inventors actually come in person and put it into effect within a specified time, and the idea of making white salt in England directly from seawater was an urgent one. England had some salt sources of its own: there were salt springs in Cheshire; there were also some pans boiling seawater in the north-west and -east where there was plentiful coal. But this production was limited, and the country was still overwhelmingly reliant on imports of bay salt from France and white salt from the Low Countries—imports that left England at the mercy of its ancient enemy and an increasingly hostile Catholic superpower. At the very moment that Cecil sent his letter to Seeler, an English army was entrenching itself at Le Havre in Normandy, in aid of the French Protestant rebels, and the Habsburgs had imposed an embargo on English trade. Any means of making England less economically reliant on its rivals was not only welcome, but to be eagerly sought.

Yet for some reason, Seeler delayed coming to England. Perhaps it was down to the disruption of war, or the major plague that gripped much of northern Europe that year. Perhaps he was just too busy trying to make the invention work in Germany. We just don’t know. But it meant that the partners ended up getting their next patent in a land they were less familiar with, if at all: Scotland.

The syndicate’s man in Scotland was one Angelo Mannelli, who arrived in Edinburgh at the court of Mary Queen of Scots in late January 1563, and about a month later had negotiated a whopping 50-year patent for the invention.³¹ Mannelli was probably a cousin of the Cavalcanti brothers—their mother was a Mannelli, another of the great patrician families of Florence.³² A wealthy merchant based between London and Antwerp, much like the rest of the Italian partners, just a year earlier he had lent money to the English crown.³³ But what’s most intriguing about Mannelli is that he also appears to have been sent there, not just on the syndicate’s initiative, but on Cecil’s. The evidence of Mannelli’s activities are slim, but Seeler and Holzschuher’s invention seems to have been promoted in Scotland at the instigation of the English state.

Why do I think this? Well almost half a century later, by then having reached his nineties, Francesco Berti recounted in a petition to Cecil’s son, as well as in his own will, that it was Cecil’s interest in the salt project that was “the first occasion to bring me to the knowledge and so to employment of the Queen of Scots”. Tantalisingly, Berti even mentions enclosing a fuller account with his petition of how it all came about, and that he had also held onto various letters sent to him in Antwerp by Cecil about the matter. Frustratingly, I’ve been unable to track them down.³⁴ But somewhat confirming Berti’s account is a letter sent to Cecil by the English ambassador in Scotland at the time, Thomas Randolph, who occasionally reported on Mannelli’s activities.

About a month after having noted the Florentine’s arrival, Randolph referred to the deal that Mannelli had struck with the Queen of Scots for the salt patent. But, curiously, he discussed it as though Cecil already knows what it’s all about, specifically not giving him any more details about it because he knows, he says, that Mannelli “either has or will make your honour privy” to them. It’s as clear an indication as we could hope for, absent Mannelli’s own letters, that he was directly corresponding with Cecil about the matter. Indeed, it even sounds like Randolph had been aiding the venture, trying to convince the Scottish court that Mannelli wasn’t just some sort of English spy. He adds, with what sounds to me like frustration, that “it cannot be beaten out of some men’s heads but he came about some other purpose. I find no cause why they should suspect.”³⁵

So much for the scraps of surviving evidence. But why would Cecil be promoting a salt invention in Scotland? Much like Philip II, he was surely motivated by strategic concerns. Just a few years earlier, Cecil had helped the Protestants in Scotland to conduct a coup against Mary’s regent, her French mother, whose rule had been upheld by French troops—a coup that, funnily enough, had partly also been motivated a suspicion that she was trying to tax and monopolise Scotland’s salt. After the French had been driven out, however, Mary herself—a Catholic with a strong claim to the English throne as well—had arrived from France to rule in person. Cecil must have feared that if Mary could consolidate her rule of Scotland, she might eventually undermine its recent Protestant revolution and bring it back under the malign influences of both France and the Pope.

So what the Seeler-Holzschuher luftgradierung offered was a subtle, almost imperceptible means of reducing any remaining French influence in Scotland by severing one of the main commercial ties between the two countries. Although the Scots sometimes made salt from seawater, burning their plentiful coal along the coast to evaporate it in lead or iron pans, the country was still generally reliant on cheap imports of bay salt from France. If superior white salt could be made so cheaply in Scotland that it was cheaper than even imported and inferior bay salt, then that trading connection could be eliminated entirely; and so the proportion of Scottish commerce with England would be all the greater, increasing the importance of the financial ties and acquaintance to bind them ever firmer in friendship. Promoting the salt invention in Scotland was not one of Cecil’s priorities of course—he had a lot else on his plate—but it could do some good and cost him nothing to give it a try.

Either way, and for reasons unknown, it wasn’t until almost a year later that the invention actually began to be applied outside of Germany. Seeler arrived in the Low Countries with machinery and workmen at the end of December 1563, hopped over to England about a week later to sign for his patent there—a 20-year monopoly on the manufacture of white salt in England, in his name and de Roeux’s,³⁶ from which Elizabeth I would take a cut of 10%—and then returned to the Low Countries to oversee the invention’s trial near Bergen-op-Zoom.³⁷

Then, on 1 February 1564, the patent was re-issued for a third time in the Low Countries. In what appears to have been a deal to restart the 20-year expiration date for the monopoly—there may have been other concessions, but the brief description of the new contract is from 1913, the original source in a Naples archive having unfortunately been destroyed in the Second World War—Philip II now got an even greater share of the global profits. Rather than just a 1% share of the profits in other coastal countries, he was now to get a full quarter of the profits from the patents that had already been acquired in both Scotland and England as well.

How did the Protestant governments of England and Scotland react to the extraordinary intervention by a hostile Catholic power into their salt-based industrial strategies? Well, they weren’t told. The new contract, signed on behalf of the syndicate by Francesco Berti and Stiatta Cavalcanti, was actually with yet another fellow Florentine—one Tomasso Baroncelli, whose chief role was to act as a front-man in order to conceal the Habsburg government’s share.

Baroncelli was an enthusiastic promoter of various schemes to raise revenue for the Habsburg government in the Low Countries, which was led by Philip’s illegitimate half-sister Margaret. His proposals to Margaret included a plan to drive up the price of gunpowder, to tax grain exports, and to create a state monopoly on lotteries. But because he also had frequent commercial dealings with the English nobility, acting as their agent in Antwerp to procure all sorts of luxuries, he was an ideal person to join the partnership without raising suspicion.

The deception worked. In late April 1564 the first pans, instruments, and technicians—superintended in Seeler’s stead by one Hans Müller—arrived in England to set up a saltwork at Dover.³⁸ Within weeks another group of Seeler’s men had arrived in Scotland as well.³⁹ And just a few months later, for reasons I’ve not been able to establish, the patent in England was even reissued solely in Baroncelli’s name.

The monopoly on the manufacture of all white salt in England from seawater—what Cecil had hoped would become an economic bulwark against Catholic domination—was now secretly under the management of the increasingly hostile Habsburgs. Indeed, Baroncelli’s agent in England was one Roberto Ridolfi, another Florentine merchant who just a few years later would plot with the Pope to depose Elizabeth I.⁴⁰

And on that cliffhanger… Until next time!

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1. One secondary source suggests he was born in Hall in 1520 and died at Augsburg in 1575, but I’ve been unable to follow the citations to confirm it, and some of other details from it are incorrect.

2. Vaissière, Pierre de. La découverte à Augsbourg des instruments mécaniques du monnayage moderne: et leur importation en France en 1550 d’après les dépêches de Charles de Marillac, Ambassadeur de France. Ricard Frères, 1892, particularly p.25. Annoyingly, the French correspondence doesn’t give the inventor’s name. Sometimes this 1550 machine is ascribed to a Max Schwab, so Seeler’s may have been different.

3. Seeler was nominated to the post by the counts of Stollberg, who as heirs of the counts of Königstein in 1535, had a hereditary right to appoint the masters of the three imperial mints, at Nordlingen, Frankfurt, and Augsburg. It is unclear to me whether or not Seeler simultaneously had the mastership of the other two imperial mints as well. One reference work suggests he was the mint master at Nordlingen, and another says he was in Frankfurt on minting business in 1560, both of which are suggestive, but the German sources are so difficult to access that I’ve been unable to follow any of it up.

4. Graham Hollister-Short, ‘The Other Side of the Coin: Wood Transport Systems in Pre-Industrial Europe’, in History of Technology, ed. Graham Hollister-Short and Frank James, vol. 16 (Bloomsbury, 1994), pp.80-1

5. I shall go into the detail of how I have arrived at this conclusion in Part II, because much of the reasoning is only intelligible when readers are familiar with what the syndicate was up to in 1565-66.

6. Nelson, Jennifer. ‘Keeping the Basilisk Rolling: A War Machine in the Holzschuher Testament of 1558’. Art History 44, no. 2 (2021): 342–70, speculates that the 1558 patent may have been for the inventions described in his will rather than for the salt-making process. She bases this speculation on the idea that Holzschuher did not attempt to commercialise it until 1562, but this is incorrect—the first proposal was in 1559 to the Duke of Bavaria. It is also simply highly unlikely that he would have patented the inventions described in the will, which were to be kept secret until his heirs were ready to commercialise them. The whole point of a patent is to be able to reveal a secret without worrying about someone else exploiting it, and the moment a patent is granted the clock starts ticking to do so as rapidly as possible before its term expires.

7. Cotton Vespasian F/III f.188

8. Holzschuher’s role in the recoinage has never been noticed before. He describes it in a letter to William Cecil on 27 April 1566, SP 70/83 f.220, which had been mistakenly calendered as being from a “Loftschuher”. This was a major find for me, in which Holzschuher not only describes the salt patent syndicate, but notes that he was the technician for the recoinage in 1561, going in person with a team of fifty expert metallurgists. For Caspar Seeler’s warrant from the Queen to undertake the recoinage, dated 5 December 1560, see SP 12/14 f.106.

9. For their patent, dated 12 October 1562, see Dodt van Flensburg, J. J., ed. Archief Voor Kerkelijke En Wereldlijke Geschiedenis van Nederland, Meer Bepaaldelijk van Utrecht. Vol. 3. N. van der Monde, 1843, pp.76-8

10. Ibid, p.79. The much smaller fishery of cod, ling, and pollock, consumed only 8,500 barrels each year of Spanish bay salt from El Puerto de Santa Maria on the Bay of Cadiz.

11. Goris, J. A. Étude sur les colonies marchandes méridionales (portugais, espagnols, italiens) à Anvers, de 1488 à 1567. Burt Franklin, 1925 [1971 reprint], p.465

12. Naples had over 200,000 souls; the next largest city in Philip II’s empire was likely Antwerp with 100,000. Seville had about 70,000, and Madrid was far smaller.

13. Goris, pp.465-71

14. This did not just include a 1% royalty from all salt that they produced in other coastal countries, but even a 1% royalty of any reward they received from such countries for simply revealing the details of the technique, should they refuse to grant monopolies there.

15. Richardson, W. C., ed. The Report of the Royal Commission of 1552. West Virginia University Library, 1974, p.30 — the annuities paid to strangers included £40 paid to “Franasco Bertie” since 17 October 1546.

16. Gerretsen, Jan Hendrik. Micronius: zijn leven, zijn geschriften, zijn geestesrichting. H. Ten Hoet, 1895, pp.12-3. Berti was responsible for making the Protestant duchess of Suffolk aware of the religious needs of the refugees in London, and thereby persuading King Edward VI to take action and found the German Church, where Jan Łaski preached. See also Lindeboom, Johannes. Austin Friars; History of the Dutch Reformed Church in London, 1550-1950. M. Nijhoff, 1950, p.6.

17. SP 12/2, f.212 is a draft English patent of February 1559 to allow Berti to conduct 10,000 tons-worth of trade with France, even when it was at war with England.

18. SP 70/43 f.76, a letter from Eric XIV of Sweden to Elizabeth I notes that Berti had recently been in Sweden on business, and was thereafter at Lübeck.

19. Christophe d’Assonleville’s secret note, as transcribed in de Lettenhove, Baron Kervyn, ed. Relations politiques des Pays-Bas et de l’Angleterre, sous le règne de Philippe II, Tome III, Régence de la Duchesse de Parme, Deuxième partie (28 avril 1562-13 mars 1564). F. Hayez, 1882, pp.438-444.

20. Adams, Simon, ed. Household Accounts and Disbursements Books of Robert Dudley, Earl of Leicester. Vol. 6. Camden Fifth Series. Royal Historical Society, 1995, pp.40-1, 125. Dudley’s mother, the duchess of Northumberland, owed £133 6s 8d to Berti upon her death on 22 January 1555. It strongly suggests that Berti had lent money to her husband, the Duke of Northumberland, too. In late 1560, Robert Dudley repaid him a whopping £719 due from a loan.

21. SP 70/40 f.77. John Keyle, when interrogated over his involvement in egging on the Swedish match, says that it was only the day he left for Sweden that he first had a proper conversation with Gyllenstierna, obtaining a passport from him only when he assured him that he had not been sent there by Berti to act against him.

22. On 27 July 1562, John Keyle wrote to Gyllenstierna from London that Berti “persists always in his old disgraceful claim, that is, that [King Erik] owes him a great deal of money”, SP 70/39 f.173. Perhaps Berti had lent money to Erik directly, but I think it much more likely that he was among the many London-based merchants who lent to Gyllenstierna and Erik’s siblings, John Duke of Finland and Princess Cecilia to support their embassies, and then ended up losing a great deal of money. In a 1583 memorial concerning Sweden (SP 95/1 f.12), a debt of £12,167 was still outstanding, paid to Gyllenstierna in 1561-2. The merchants were Sir Lionel Duckett, Sir William Hewitt, Geoffrey Duckett, Edward Osborne, Richard Springham, and John Dymock. (See also a mention of this debt from 24 September 1563, Royal MS 13 B I, f.120, in a letter to the King of Denmark asking for safe passage for an envoy to Sweden to sue for the debt). Of these, Duckett was Berti’s co-investor in English mining projects, Springham was one of the creditors of Berti’s agent in Scotland, Angelo Mannelli, as discussed below, and Osborne was by 1566 involved in the management of the salt patent in England too. That Berti himself had lent in this way to the Swedes is hinted at by a contract to promote the salt patent in Sweden, dated 31 March 1566, which winded up being captured by Danish privateers or warships en route to Sweden, VA XI, Tyske Kancelli II, s. 210 TKUA, Speciel del, England 50-51, no.22; in this, Princess Cecilia is said to have violated an earlier contract in December 1565, to the damage of Lord William Cobham, Berti, and Berti’s associates.

23. SP 70/41 f.109 is a letter from Gyllenstierna to James Goldborne, dated 12 September 1562, which gives a brief account of Berti’s actions. One of Berti’s claims was that “she had commerce with a certain earl who died in Italy”: this is certainly an allusion to Courtenay. When Mary I came to the throne in 1553—and he was released from the Tower of London, where he had largely grown up—it was hoped by many that they might marry, as Courtenay was also a royal cousin. But when she opted for Philip II he turned his hopes to Elizabeth instead. Courtenay and Elizabeth were both implicated in the Wyatt rebellion in early 1554, and they were both committed to the Tower of London, after which they were both under house arrest. He was released in late 1555, going to Italy where he died the following year.

24. SP 70/147/1 f.172, letter written 22 January 1563 from Stockholm by Geoffrey Preston to William Herle.

25. See Erik’s letter to Elizabeth, dated 20 October 1562, SP 70/43 f.76.

26. On 4 August 1562, leaked letters allowed for key members of the pro-Swedish party to be arrested and interrogated—including one of the queen’s oldest friends, Kat Ashley. According to Habsburg diplomatic dispatches, the pro-Swedish faction included the earl of Arundel and earl of Hertford. See de Lettenhove, cited above, p.108, in a letter dated 13 August 1562 from the Bishop of Aquila to the duchess of Parma, Philip II’s regent in the Low Countries.

27. See d’Assonleville’s letter, as above. The high-ranking ministers were Parr’s husband, the marquis of Northampton, and the duke of Norfolk, who refused on the grounds that Berti might be away in the queen’s service. Both were known members of the pro-Dudley party. Just a few months earlier Norfolk had cornered the queen at a ceremony of the Order of the Garter to beseech her to marry, and to Dudley in particular. See: Archer, Ian W., Simon Adams, and G. W. Bernard, eds. ‘A “Journal” of Matters of State Happened from Time to Time as Well within and without the Realm from and before the Death of King Edw. the 6th until the Yere 1562’. In Religion , Politics, and Society in Sixteenth-Century England, vol. 22. Camden Fifth Series. Cambridge University Press, 2003, p.100.

28. In a letter dated 27 May 1564 (Royal MS 13 B I, f.118), Elizabeth I wrote to Cosimo I of Florence to recommend Guido for his return to Florence, stating that he had first come with his father to England when only a small boy, barely ten years old. Their father Giovanni died in 1542. The brothers were granted an import licence for three years in November 1546 (SP 4/1 f.105).

29. See d’Assonleville, who names all of them in the same letter; it is striking that all of them were involved with the salt patent too, and at around the same time.

30. SP 12/28 f.17

31. SP 52/8 f.12. The English ambassador, Thomas Randolph, reported that one of Lord Arundel’s servants was in Mannelli’s company. It’s unclear if this had anything to do with the salt patent or was simply a coincidence. The calendar mistakenly says that it was a servant of the Lord Admiral. I’ve not been able to find any further mention of this servant in Randolph’s dispatches.

32. Their father, Giovanni di Lorenzo Cavalcanti (d.1542) was married to a Ginevra Mannelli. See Cassia Albuquerque, Fabio Arruda de Lima, Marcelo Bezerra Cavalcanti, Francisco Antonio Doria, Os Cavalcantis, na Itália, no Brasil, Jardim da Casa, 2011, pp.23, 25-7

33. SP 12/21 f.152

34. The quotation is in a petition from Berti to Robert Cecil, dated 4 February 1609 (SP 14/43 f.85). Berti’s will, made out on 21 March 1610 states that it was by Cecil’s “means in the saltworks whereby I first became known to the said Queen, his Majesty’s [James VI/I’s] mother”. Berti notes in the will that the petition, along with a fuller account of the matter, had been given to Robert Cecil via John Linvingston, a gentleman of James I’s bedchamber. The will also notes that Berti’s full accounts regarding the salt matter in Scotland had been taken from him by Mr Fleetwood, recorder of London, and he “could never have them again”.

35. SP 52/8 f.25

36. There is a surviving copy of this patent in the Folger Shakespeare Library, Z.c.44 (3). This copy is date 14 March 1564, and with a deadline to set up by 24 June, which differs from the version on the patent rolls dated 15 January and with a deadline of 1 May. The discrepancy is explained by a letter sent by Berti to Seler’s attorney in England, Thomas Heneage, dated 11 April, SP 12/33 f.113, in which he notes that the pans and other instruments are on their way to England, but so delayed that the 1 May deadline is likely to be missed. He notes that he and Richard Clough, the right hand man of Elizabeth I’s financial agent in Antwerp, Thomas Gresham, had promised Seeler that the queen “should not stick for a month, or else he would not have signed the indenture”, and so asked Heneage to “see that clause so provided for that he come in no danger”. Presumably either Heneage had already foreseen and got the patent amended and re-issued in march, or else it was re-issued in April with the new deadline and the date of issue back-dated (there are other cases of this happening).

37. Goris, p.473; see also a letter sent by Seeler to Cecil on 10 April 1564 from Bergen-op-Zoom.

38. SP 70/70 f.39

39. SP 52/9 f.65

40. L'osservatore fiorentino sugli edifizj della sua patria (1821), Volume 4, p.98 mentions that a patent to Baroncelli, dated 16 November 1564 (somewhat later than the October date on the patent rolls) was in 1821 was in the possession of the Carcherelli family, having been inherited from members of the Paganelli family. What the description reveals is that Baroncelli’s agents in England were Roberto Ridolfi and an Englishman whose name is rendered as “Pietro Brudey”, perhaps a Peter Brodie or Bradley, who I’ve been unable to find.