Historical story

Digital treasure hunting in the Sound Toll Registers

Nearly two million ships had to pay tolls to the Danish kings between 1497 and 1857 when they passed through the Sound. These passages were noted and are now, almost, all digitized. A wealth of information is revealed.

The mega project that leads to the complete digitization of the so-called Sound Toll Registers is almost completed. About seven percent to go. A Japanese PhD student described the already available data on shipping passages to and from the Baltic Sea as 'more exciting than pornography', according to his supervising professor from Kyoto University. And there was no irony in that.


The 'mother trade', that's what merchant shipping on the Baltic Sea is called. From the end of the Middle Ages, the Dutch fleet roamed – first reluctantly, later growing spectacularly – to the Baltic coast to supply herring, salt and sugar in exchange for ship's timber, masts, tar and iron. Products that in the Low Countries formed the basis of the unprecedented military and commercial power of the Republic in the Golden Age. Without wood no ships; without ships no trade. Hence 'mother trade'.

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From about 1500, this trade route steadily increased in size and profitability. But to reach that beckoning Baltic Sea via the North Sea and the waters around Denmark, skippers, whether they wanted to or not, had to navigate one narrow passage:the Sound, in English 'the Sound'. And there, at Danish Helsingør and now Swedish Helsingborg, where the straits are only 4.5 kilometers away, toll collectors stood ready to collect their tokens – century after century, a lucrative business that the Danish kings, who at the time also owned 'the other side' in present-day Sweden, became very wealthy.

Digitization paper mountain

Fortunately for historians, generations of industrious clerks recorded each passage in the toll booth. Over the centuries, the collection of recorded passages grew to the immense number of 1.8 million. Until the moment when the European states involved, led by a great power such as the United Kingdom, had had enough of the cumbersome toll payments in the middle of the nineteenth century and bought the Danish monarch off in one fell swoop.

What to do now with the inscrutable mountain of paper in the national archive in Copenhagen, which has now been designated a UNESCO World Heritage Site? That collection of almost two million 'pages' that states where the ship came from, where it was sailing to, what the cargo was and the origin and name of the skipper? There was only one solution:digitize and make it searchable.

Researchers from the University of Groningen and Tresoar started it about ten years ago, using the sheltered employment facility in Nijmegen. From 2013 help came from an army of volunteers and in 2020 (sic!), the database is expected to be finalized. Not that we have to wait so long for the results:the data has been online since 2011, with an ever-growing amount of data.

There are now 1.7 million digitized passages on the web. There are still 125,000 missing. That is a total of 242,000 registrations, because one passage could cover several registrations. For example, the skipper also had to pay fire money – a contribution for the maintenance of light beacons along the coast – in addition to the toll. The height of this was determined on the basis of the nature of the cargo and size of the ship. After 1633, those separate quotations were abolished.

Different spelling

The researcher and project leader from the very beginning is Jan Willem Veluwenkamp. Like co-project leader on behalf of Tresoar Siem van der Woude in a distant past, he hoped to be ready in 2011 (later it was 2013), but he almost bit his teeth on the tough Danish fare. Although he retired this year, he says he will eat 'his hat' if the project is not completed in 2020.

Veluwenkamp:“At that time there was no standard spelling in the written language, not even in Danish. People just wrote something, as long as it remained understandable. We found two hundred different spellings for the name Amsterdam in the registers. And how did a Danish clerk in the seventeenth century spell Boulogne-sur-Mer, in answer to the question "Where are you from?" It varied quite a bit. Not bad then, but very difficult for our digital copyists.”

Artery of the European economy

The Sound was the artery of the European economy. Half of the ships that passed through it came from the Netherlands:in the seventeenth century with a dominance of Dutch ships, in the course of the eighteenth century ships from Friesland took over that role. Sometimes a hundred ships – types like kofschip, smackschip, or the larger flute – were waiting in the Kattegat or Skagerrak for favorable winds. Gradually, other European nationalities joined the trade. Luxury products such as French wine and tobacco also conquered the hinterland via port cities such as Riga, Danzig and Stettin.

With a few search terms entered and a mouse click here and there, you can see in a few moments that in the eighteenth century coffee was mainly exported from France to the Baltic Sea. Between 1700 and 1720 the Republic still had the upper hand, albeit on a modest scale, with an export of 1,748 pounds and France 0. But twenty years later, between 1741-1760, the Republic was completely outflanked by the French:76 percent (more than two million pounds of coffee) at 16 percent 'for us' (also significant in volume).

Unlimited possibilities

And what does this information say? Veluwenkamp:“Everything about the development of the various fleets, that of the distribution centers, the specializations, the maritime and commercial dominant position of the countries involved and of the buyers:because coffee is a luxury product and developing countries such as Russia apparently had , Poland and the Baltic States the money for it. You should not be surprised if after some time products sold as far as Vienna that were supplied via the Baltic Sea trade.”

If you want to know exactly how many skippers from Oude Pekela passed the Sound in a westerly direction between 1760 and 1800 (a peak of 160 in the year 1792, by the way) you can easily recall this. Departure ports Memel and Pillau dominated here by far, with Stettin and Königsberg coming in close second.

In short, the possibilities are limitless. Even without a specific search query you can browse endlessly in it. Making the toll books searchable and sortable online is an essential resource for understanding Europe's economic history for all to see. And that makes the fascination of the Japanese PhD student a little more understandable.