The early modern battle for Baltic supremacy

Looking at the history of the Baltic Sea region we see a succession of powers that tried to control and close the sea: the Hanse, Denmark, Sweden, Imperial and then Nazi Germany and, finally, the Soviet Union. The struggle between different would-be hegemons or imperial powers is a familiar one, but it needs to be complemented by an account of the powers that wanted to maintain an open sea, the Dutch Republic and England/Britain. The monopolistic powers and the trading ones had different economic philosophies: during the early modern era, Denmark and Sweden pursued a mercantilist political economy, and the Dutch, following Grotius, saw free trade as a natural right. Later, Nazi Germany would follow the principles of plunder and autarky, while the Soviet Union followed those of a planned communist economy.

There is a tug of war between the two principles and the powers associated with them: the idea of the free sea, open to commerce by all parties, and the ambition to claim a monopoly over a body of water – in this case the Baltic Sea – and the trade moving through it.

The struggle over the Baltic was essentially a conflict over the control of trade flows and maritime lines of communication. As so memorably stated by Knud V. Jespersen: ‘In the 17th century, the Baltic played the same role for the two trading and shipping nations of western Europe, the Dutch Republic and England, as the Persian Gulf with its oil reserves plays for the industrial nations of the western world today.’ The region was a crucial supplier of timber, tar, hemp – resources upon which the maritime powers depended.

The Dutch cities and later the united Dutch Republic had been the most important commercial presence in the Baltic Sea since the end of the Middle Ages. Already, by 1497, the Dutch had the largest share of all trade passing through the straits of Denmark. After the 1590s, Dutch influence in culture, economy and politics started to pervade the region.

Yet in most of the conventional works on the geopolitics of the Baltic, particularly its military history, the Dutch are assigned a quite peripheral role. Perhaps this is because the Netherlands is not a Baltic country, or perhaps because the Dutch never tried to conquer any territory here and hence their influence cannot easily be demonstrated on the coloured maps that show the fluctuating fortunes of the regional powers and their imperial projects. Power in terms of commercial strength, administrative know-how and influential legal and political ideas are not the stuff of which great historical dramas are made, and hence it is tempting to relegate them to the sidelines in favour of kings of horseback. But the dynamics of power during the early modern age cannot be adequately understood without these factors – and thus the Dutch play an important role in our tale.

From the late Middle Ages, it was Denmark that initially emerged as the most dominant power in the Baltic Sea. It had sought to extend its power across the North Sea during the Viking era and the High Middle Ages, but after the Norman Conquest turned eastwards to the Baltic Sea. Not only did it possess both sides of the Sound; it also possessed substantial territories in what is now northern Germany. Once it acquired Estonia and Gotland, it was the territorial master of the region. This became complete when Norway and Sweden were brought into the Union of Kalmar in 1397. Still, commerce remained in the hands of the all-powerful city league of the Hanse until the 16th century.

Geopolitics and rivalry in the Baltic Sea started to become much more dynamic once the Teutonic Order, which had dominated the eastern Baltic, had collapsed. The city of Reval (now Tallinn, capital of Estonia) , fearing Russian influence, appealed for protection under the Swedish crown, which gladly accepted. The upstart Sweden now controlled both shores of the Gulf of Finland as well as the mouth of the Neva and thus blocked Russian access to the Baltic Sea. Trade had to go through ports such as Riga, which was under Polish overlordship, and Viborg, a Swedish town. Meanwhile Denmark conquered Saarema (Ösel), opening a new front in the rivalry between the two powers.

Sweden broke off from the Union of Kalmar under Gustavus I Vasa in 1523 and gradually began to challenge Denmark as an actor in the Baltic. Through a series of wars in the late-16th century, Sweden gained recognition of its independence, seized Estonia and unsuccessfully challenged Denmark-Norway’s prerogatives in the Arctic. At the same time, the Hanse faded into insignificance.

The first intervention from the Dutch in the Baltic was made with England, namely restraining Denmark in the Kalmar War (1611–13) against Sweden. The conflict ended with the recognition of Denmark’s power over the Sami-dominated Arctic lands, but also, crucially, with Sweden being granted exceptions from the toll duties in the Sound of Öresund.

At the beginning of the 17th century, Sweden’s geopolitical position was far from favourable. The realm was located on the Scandinavian peninsula and in Finland, but this considerable territory constantly ran the risk of becoming cut off from the wider world. By possessing both sides of the Sound, Denmark controlled entry into the Baltic and ownership of the island chain of Bornholm, Gotland and Ösel/Hiiumaa, which gave its powerful navy an opportunity to encircle Sweden.

Moscow had just recently emerged as the most powerful of the Russian principalities after defeating the Mongols and the Siberian Khanates. It, too, was largely cut off from the seas: the Crimean Khanate controlled the Black Sea, while only a sliver of land at the mouth of the Gulf of Finland provided an opening to a part of the Baltic that was not controlled by foreign powers. Once at sea, the problem of Danish supremacy remained. This was alleviated, but certainly not resolved, by the opening of the northern trade route into the White Sea by English explorers and the founding of Archangel in 1584. The latter allowed Dutch and English sailors who braved the stormy waters to trade with Russia, who gained a ‘window on Europe’, through which capital, goods and ideas could flow into the country.

Thus, two underdeveloped but ambitious powers sought to break out of their isolation and enter the European system on their own terms, while Denmark – the north European superpower of the late Middle Ages – attempted to retain its position.

European politics had been systematic and continent-wide for several centuries, but at this time it had strong subsystems. We can observe a west European one, a Mediterranean one, a central-eastern European one and, finally, a northern-eastern European one centred around the Baltic. Although these were not fully integrated and certain uniquely regional dynamics were at play, none of them operated in isolation. This goes least of all for the Baltic subsystem. Trade with the rest of the world was crucial for all of the powers concerned and resources such as grain, iron and herring from the Baltic were important for the west European powers – primarily the Dutch Republic and England.

The Thirty Years War (1618-48) was Europe’s main cataclysm before the two world wars. The majority of the fighting took place in the Holy Roman Empire, but the two Baltic powers, Denmark and Sweden, were highly involved. Both were aggressive, rapacious and well equipped for war. They were also Protestant powers, which provided them with a real incentive for intervening in what had been a war between German princes and the Habsburg emperor.

Denmark was first on the scene, as Christian IV went to war in 1625. For Denmark, the war only lasted four hard years and ended in dishonour and disaster.

In contrast, Sweden’s role lasted 18 years and resulted in a triumphant ascension to the position of one of the great powers of Europe as well as the leading power in the Baltic. At the Peace of Westphalia in 1648, Sweden was not only granted the status of protector of the constitution of the Holy Roman Empire, but also received a foothold on the southern shore of the sea in the shape of Pomerania and Rügen. As the islands of Gotland and Saaremaa (Ösel) had been seized from Denmark in 1645, the threat of encirclement was now gone. Instead, the isolated and besieged power had become a hegemon.

Having achieved so many of their goals, the elites of Sweden turned their eyes towards a new prize: the Commonwealth of Poland-Lithuania. Ever since the birth of Sigismund Vasa in 1566, Sweden and the commonwealth had shared a complicated relationship. Sigismund’s parents were King John III of Sweden and Catherine Jagiellon of Poland, and he was thus heir to both polities. His reign in Sweden was brief (1592–99) but he was king of Poland between 1587 and 1632. Now, in 1648, his youngest son, John II Casimir Vasa, sat on the Polish throne and he had a claim to the throne of Sweden – an intolerable situation to Stockholm. King Charles X Gustav of Sweden invaded the commonwealth from the west, while Muscovite Russia invaded from the east. This war, known in Polish as potop szwedski (‘the Swedish deluge’), was one of the most destructive episodes in Polish history. For Sweden, the war ended with a wealth of plunder, the abdication of John II Casimir and the ousting of the Vasas from the Polish throne.

Having removed a major dynastic threat to the Swedish crown and left a Baltic rival in ruins, Charles X Gustav brought the war to Sweden’s oldest enemy, Denmark. A quick campaign in Schleswig, Holstein and Jutland seemed to stall at the onset of winter in 1658. Usually, early modern armies did not fight during the cold season but went into winter quarters to recuperate, repair their kit and await the arrival of spring. Not this time. The straits of the Belt Sea had frozen over and that made a daring ploy possible. Having ordered some preliminary tests and said the customary prayers, the Swedish king marched his army across the ice between the Danish islands. Over a period of two weeks a series of crossings were made until the army reached the island of Zealand, where Copenhagen is located. This early exercise in manoeuvre warfare took the Danes completely by surprise, and, with the capital facing a mortal threat, they had no option but to capitulate.

The peace of Roskilde in 1658 was one of the greatest defeats in Danish history as Skåne, Blekinge, Halland, Bornholm and the Norwegian provinces of Bohuslän and Trondheim had to be ceded. The loss of eastern Denmark was a crushing blow as the terrae scania had been part of the core of the realm since the tenth century. Not only was it prime agricultural land and the seat of the Archbishopric of Lund, it also ensured Danish control over the Sound of Öresund. With the loss of Skåne, Denmark could no longer exercise effective control over the western approaches to the Baltic Sea.

Not satisfied with capturing the eastern half of Denmark, Sweden went to war again almost immediately after the Treaty of Roskilde was signed. Now the war aims of Charles X Gustav were even more ambitious: wiping out Denmark. However, as so often in early modern European history, conflicts of this magnitude rarely played out between only two antagonists. Instead, systemic dimensions intervened. The idea of a balance of power was a central to political thinking of the time. On a European level, what monarchs feared most was any attempt to establish a ‘universal empire’ that would subjugate all other polities under a single crown. This danger had been the underlying motivation for diverse coalitions against the Habsburgs since the 16th century and it would be the animating force against Louis XIV’s attempt to establish a continent-wide hegemony. Charles X Gustav did not harbour ambitions to subject all of Europe to his will, but on a regional level his aggression against Denmark triggered similar resistance.

Viewed from the Hague, the prospect of Sweden controlling the Sound and reigning supreme in the Baltic without any other power that could balance and limit its influence was simply unacceptable. Two maxims reigned supreme in Dutch Baltic policy: to play Denmark and Sweden off against each other so neither would come to dominate the Baltic; and to ensure commercial freedom.

Furthermore, since the struggle against France was the most important rivalry to the Dutch, it was vital to counter French influence in the area. The Swedish aggression was not only a mortal peril for Denmark; it also threatened to overturn Dutch policy in the Baltic. The Republic quickly dispatched its powerful fleet, which had rescued Copenhagen in 1659. It was not the first time that the Dutch had used their naval might in an intervention in the region. In 1645 they had sent their fleet to Copenhagen in a symbolic rebuttal of Danish claims, and in 1654 they relieved Danzig, without bloodshed, from the Swedish siege. On land, the Swedish army was defeated by an unlikely coalition of the Brandenburgers, the Dutch and the Habsburgs. Together with England, the Dutch Republic forced a quick end to the war and restored peace with a modicum of balance to the Baltic.

The Dutch Republic and Sweden clashed again in the 1670s during the Franco-Dutch War (1672-78). Sweden and its sponsor France were on the losing side against a considerable coalition. In the 1679 Peace of Nijmegen, Sweden had to grant mutual freedom of trade to the Dutch. As was the case with the British Empire in the 19th century, free trade was in the interest of the strongest commercial power, and in the 16th century it was certainly a core interest for the Dutch. Sweden, meanwhile, moved in the opposite direction, becoming increasingly mercantilist and even limiting trade rights in its own empire as only a few cities were given the privilege of pursuing foreign trade.

Balance of power dynamics intervened time and again in the fortunes of the two aspiring Scandinavian hegemons. Sweden’s successes in building a Baltic empire engendered a considerable sense of threat among its neighbours. When Charles XI, the seasoned warrior king, died in 1697, Sweden’s enemies formed a league. The stars seemed to have aligned for a move to dismantle the hegemonic power: the new king, Charles XII, was only 15 at the time of his coronation. With a young and inexperienced king and commander-in-chief, Sweden appeared politically and militarily fragile. Three years later, in 1700, the confederates Denmark, Poland-Saxony and Russia declared war against Sweden. However, their expectation of a swift victory was confounded.

First, Denmark was knocked out of the war by the combined effort of Dutch, English and Swedish naval forces, who bombarded Copenhagen and forced the Danes to sue for peace. Second, Russia was dramatically defeated at the Battle of Narva in 1700. Unfortunately for his country, the Russian offer of peace was rejected by the young Swedish king. Third, a long campaign through Poland and Saxony followed, in which Swedish armies once more laid waste to the commonwealth.

In western Europe, the War of the Spanish Succession (1700-13/14) raged at the same time as the Northern War. When Charles XII and his seasoned army camped at Altranstädt in Saxony, the other powers of Europe feared that he would get involved in the Spanish war and thus join the western and eastern European systems. The English commander, the Duke of Marlborough, was sent as an envoy to parley with the Swedish monarch and dissuade him from extending his war into western Europe. Whether it was the duke’s intervention that swayed Charles XII is difficult to tell, but he remained adamant that he would pursue his foes around the Baltic.

Although he did not venture into the western European theatres of war, the young king significantly extended the war beyond its original confines. In a moment of hubristic overreach, Charles XII decided that he wanted to impose a total victory upon Russia, preferably making its monarch – the equally ambitious Peter I – personally submit to him. Thus he turned the armies of Sweden eastwards and marched into Russia itself. As later invaders would find out, all-out land invasions of the Russian heartland tend to break even the most powerful forces. And break the Swedish army did. After years of exhausting marches and the occasional battle, Charles XII met Peter I on the battlefield at Poltava in 1709. The Swedish army was crushed. There was no peace until 1721, three years after the death of Charles.

In the meantime, Russian armies overran and occupied Finland and fleets of fast galleys harassed and burnt the coast of Sweden without the Swedish navy being able to stop them. These naval campaigns clearly demonstrated who was the military master of the Baltic Sea.

At the Peace of Nystad in 1721 Sweden lost Estonia, Ingria, Livonia and parts of Karelia (the provinces of Viborg and Kexholm) to Russia. Sweden’s blockade of Russia’s access to the Baltic was broken, as was the stranglehold in the Gulf of Finland. Russia had gained a secure bridgehead into the Baltic and decisively emerged onto the northern European scene.

The victory at Poltava echoed long into the Russian historical consciousness. One the major sections of the majestic Hermitage Museum in St Petersburg consists of paintings of episodes from Russian history. In the first room of this significant showcase of national identity and pride hangs a gigantic canvas that signals the start of the journey. It is Alexander Evstafyevich Kotzebue’s The Victory at Poltava. In the painting, Peter I is resplendent on his war horse, while the Swedes lower their banners to the dust and, heads bared, bow before the victorious emperor. In the foreground, two Ukrainian Cossacks – allies of the Swedes – lie exhausted.

There is an argument to be made that Russia became the next hegemon of the Baltic Sea. It had toppled Sweden from its role as a great power and reduced it militarily. Throughout the Swedish ‘Age of Liberty’, during which the country was dominated by parliament, Russia regularly intervened in Swedish politics by supporting one of the main parties. Moreover, it was now in possession of large parts of the eastern littoral. Thanks to the reforms of Peter I it was better poised to project power, both onto its erstwhile Scandinavian nemesis but also into Poland-Lithuania and into Germany. Peter the Great not only proclaimed himself emperor in the western tradition, abandoning the old title of tsar, he also built a navy and a brand new capital named after himself, which became the pre-eminent metropolis of the Baltic Sea.

Was the 18th century an age of openness or of closure in the Baltic Sea? The record is mixed. The Dutch were no longer a significant intervening force and most of the powers around the Baltic were strongly protectionist and anti-Dutch/anti-British. But it was not in Russia’s interest to close off or control the sea in the way that Denmark and Sweden had attempted to do. Russia had a territorial opening to the Baltic from 1721 onwards, but it remained highly dependent on foreign trade, capital and expertise. Knud Jensen argued 30 years ago that one of the end results of the Great Northern War (1700-21) and the humbling of both Denmark and Sweden was to open the Baltic region even further to external influences from Britain and Russia. There was a distinct downside to this development for ambitious rulers in both Scandinavian capitals but a considerable advantage in the sense of decreasing the frequency and severity of war.

The struggle over control of the networks of trade and other flows was a constant theme in Baltic geopolitics of the early modern era. Naturally, commerce and conflict have always been intertwined, but the narrowness of the Baltic, with its series of chokepoints, the number of opposing states and its importance for the rest of Europe, meant that the battle over flows and over closure versus openness was a particularly strong theme. The tension between openness and closure could also be seen as a conflict between two kinds of power: economic and political. Or, perhaps more precisely, between two principles of economy: free trade and state control.

Studying the history of the Baltic during this period illustrates how Europe was a series of nested systems. It was – and still perhaps is – a collection of discrete regions, each of which is characterised by its own aspirations, cultures and dynamics, but nevertheless connected to other parts and to the greater whole.

This essay was originally published in The Baltic Sea: A Geopolitical History, edited by Peter Haldén and published by Bokförlaget Stolpe.