The First Schleswig-Holstein War: The Beginning of Military Interposition

1848 was a turbulent but critical year in the modern history of Europe, which saw the major crisis of the so-called “Vienna system,” with politically and socially originated revolutions and revolts across the continent.

Within this context, the Duchies of Schleswig and Holstein were caught between rising nationalism and the will of the German-speaking people for unification.

The case of Schleswig and Holstein remains a minor part of that momentum, overshadowed by other major events, while also overlapped by the first Prussian-Danish war. Thus one of the first neutral interposition operation in Europe has been marginalized and largely forgotten.

The majority of Schleswig-Holsteiners were German speakers (despite a prominent minority of Danes), who believed that the inclusion of their territory within the German Federation, with its own constitution, was the optimal option for their own future.

In this light, they naturally looked to Prussia.

In Denmark, as in many other European countries, the call for a democratic constitution was initially triggered by the February riots in Paris against King Louis-Phillipe of Orleans.

The Danish Crown, in crisis, constitutionally and in terms of monarchical succession, wished to keep a firm hand on the southernmost duchies and sent military forces to crack down on the insurgents and the Prussian forces that supported them.

During the conflict, a truce was established, and a Swedish-Norwegian force, supported by a British naval squadron, was dispatched to the region, with the mandate to garrison one part of the disputed area.

This could be considered the first interposition experiment carried out by a neutral actor.

This force often at the center of skirmishes and clashes, anticipated similar situations in peacekeeping operations in the 20th century.

Finally, also, the withdrawal of the neutral force saw many clashes.

The Region

The Schleswig-Holstein situation, one of the most intricate grids because of ethnic and dynastic reasons in all of entire Europe, was seemingly solved by way of another conflict in the second half of the 19th century, and was finally resolved with a plebiscite, carried out under the joint auspices of the Allied and Associate Powers and the League of Nations after WWI.

The Schleswig-Holstein represented, as mentioned above, one of most complicate situations, due to the ethnic and dynastic quagmire of contrasting trends and interests, both local and regional.

This conflict was the mirror of several ongoing mutations in the political, economic and social landscape of the European continent.

Denmark, like many other countries in Europe, was caught in the broader transition between absolute monarchies to a constitution-led state model.

In this already complex scenario, emerged a new military model—the use of neutral force between warring parties.

In the past, there had been some cases (Italy, during the “Salt War” and in Switzerland); but the case of Schleswig-Holstein represented, for the time, one of the most coherent experiment.

It should be noted that the deployment of Swedish-Norwegian troops in Schleswig-Holstein was the transformation of initial, planned deployment in support of Denmark, into a neutral-intended intervention, representing a major change in the political stance of Stockholm.

The Political Landscape

The German communities, who lived in the duchies of Schleswig and Holstein, governed from Denmark, revolted, in April 1848, against the Copenhagen rule, inflamed by similar revolts which swept across all of Europe.

The German Federation, an organization which brought together all states of the post-Vienna Congress Germany, inflamed by self-determination and national unification principles, mandated Prussia to support the insurgents.
Facing a serious threat, Copenhagen asked help from Great Britain, Sweden-Norway and Russia.

The three foreign parties brought in their own international and regional interests to the crisis as well as their broader worldviews.

Stockholm, in one of the first examples of Nordic solidarity, and on the request of Copenhagen, sent a contingent, in May, to Denmark (4.000 out of the 15.000 men deployed in Scania), ready to intervene, supported by a large naval force.

Aside from the deployment of troops, not involved in clashes, and aside from Danes against pro-Germans and Prussians, Sweden sent to Prussia a declaration, stating that any further action against Denmark would lead Stockholm into a direct intervention into Copenhagen, a city considered vital for the strategic security of Sweden.

The mere presence of Swedish-Norwegian troops, which landed in Fyn, blocked further progression of pro-Germans forces and Prussian elements up towards the north.

However, it should be said that Sweden-Norway also asked Denmark to refrain from any action that might lead to a worsening of the crisis, like launching counteroffensives against Schleswig-Holstein, under control of the pro-Germans and Prussians.

London, following her traditional approach and policies, sought to avoid any possible change in the balance of powers in the continent, as much as possible.

The strategic position of Denmark, a key area between the North Sea and the Baltic, made the request for assistance from Copenhagen, a matter of strategic interest for Great Britain.

Russia, which since the Napoleonic wars considered Prussia her protégé, did not appreciate the liberal shift ongoing in Berlin and interpreted the move for Schleswig-Holstein, not coordinated with St. Petersburg, as a sign of political independency.

For St. Petersburg, this initiative risked dismantling the legitimacy of the political system ongoing in the continent, set up with the so-called “Vienna System.”

On British initiative, in the month of May 1848, peace negotiations were organized in London, between Prussia and Denmark, with Britain as mediator.

In the talks, it was proposed to split the territory between Schleswig and Holstein, but which was not accepted by the Danes.

Despite this initial failure, Lord Palmerston, the British Prime Minister, insisted on continuing the negotiations in Malmoe, Sweden.

The negotiations, coupled with the provisional halt to military operations, led to the signature of the first cease-fire signed in Malmoe, under the auspices of London, St. Petersburg and Stockholm.

The issued ceasefire put Berlin in an embarrassing situation, given that the German League Parliament, seated in Frankfurt am Main, did not ratify it. Consequently, the King of Prussia did not ratify it, either—while Denmark did ratify the ceasefire.

Then, a rift took place. The pro-German forces, refused to accept the ceasefire, reflecting the ambiguous stance of Berlin and Frankfurt.

In this regard, Denmark, despite talks ongoing since mid-July, on the 24th of that same month, declared the temporary armistice null and void.

Copenhagen, though it did not resume ground operations against the pro-Germans and Prussians, established a rigid naval blockade of Baltic coasts, enjoying the support of London, St. Petersburg and Stockholm, and was strongly hostile to Berlin’s refusal to ratify the truce.

A new truce was signed in Malmoe on 26 August 1848. During this truce, lasting seven months, no political results were obtained.

At the expiration of the truce, fighting erupted again between the Danish forces on the one side and the Prussians and local insurgents on the other; but this time it saw the dominance of Danish forces, testified by the Battle of Fredericia on 7 July 1849.

The Neutral Force

In Malmoe, with the reopening of war, a new session of negotiations was immediately promoted by Norway-Sweden, Russia and Great Britain, and in July 1849 led to a result.

Russia and Great Britain were strongly interested in normalization, given that their commercial trade with Prussia was heavily affected by the Danish naval blockade.

This led to a new truce for six months, which was extendable for a further six weeks.

Despite fierce resistance, Denmark accepted the idea of partition of the disputed territory (an option that emerged during talks between the other stakeholders) as the only way to solve the issue.

Prussia signed the armistice on 10 July and Denmark on the 17th.

Prussia provisionally administered Southern Schleswig and Holstein, inhabited mostly by German populations, and garrisoned the area with 6.000 troops.

Northern Schleswig, with a stronger ethnic mix, was administered by an international commission, directed by a British diplomat, along with a Prussian and one Danish deputies, thus setting up a tripartite administration, based in Flensburg.

The international commission was assisted by a force of 4,000 Swedish-Norwegian soldiers, supported by a British naval squadron and one (much smaller) Swedish-Norwegian naval force.

The Swedish-Norwegian troops arrived in Flensburg on 27 August 1849, and they policed the area, disarmed the pro-German forces and monitored the withdrawal of Danish troops back into Jutland.

The Force Commander was the Commanding Officer of the Värmland Regiment (one of the oldest units of the Royal Swedish Army), Colonel O. A. Malmborg, who for this duty was promoted Major-General.

The international presence was constantly punctuated since its arrival by serious incidents and clashes, especially with pro-German insurgents, and in-between those with the Danish-speaking irregular armed elements.

The surveillance of the line separating northern from southern Schleswig was very problematic due to the nature of the area.

The Southern Schleswig remained the base for pro-independence militias, which despite the heavy losses in the war against Denmark, remained ready to fight.

The Prussians, who were tasked to disarm them, instead supported their raids in the north.

In January 1850 a Swedish-Norwegian detachment was attacked by 800 armed units in a heavy battle, south of the demarcation line, southeast of Flensburg.

The international troops, in a recce mission, following an incursion of pro-German units, was forced to cross the demarcation line and engage the insurgents in clashes, and thus defeating them.

The mandate of the international force expired in January 1850, but was extended for other six months, as in Berlin a decisive phase of the negotiations between Prussia and Denmark, ongoing since December 1849, was taking place.

The talks required many weeks; and only on 2 July was there reached a final agreement, in which Denmark returned to exercising sovereignty over the Duchies, but with the commitment not to conduct unfair policies and/or reprisals in the German minority.

During the spring of 1850, Russia suggested that the Swedish-Norwegian force should also garrison Southern Schleswig, replacing the Prussians forces.

The proposal was rejected by Sweden, on the ground of a substantial risk of even greater involvement in dealing with a hostile, pro-German, population.

On 2 July 1850 peace was signed in Berlin between Denmark and the Prussia and German League.

The agreement allowed the withdrawal of Swedish-Norwegian and Prussian forces from their areas of responsibilities.

In late July, the Scandinavian troops left the territory. The operations of re-embarkation were characterized by incidents, heavy gunfire and several fallen among the troops and the German separatists.

At the same time Prussia withdrew its forces from southern Schleswig and Holstein. As soon as foreign forces were withdrawn, the duchies were re-occupied by the forces of Copenhagen, according to the peace treaty.

The Danish forces crushed in few days another uprising of the pro-German armed groups, which exploded immediately after the arrival of the troops of Copenhagen.

Although little known, this mission contains within itself the harbingers of future peace support missions: interim administration, approval of the parties involved in a conflict with regard to the deployment of a neutral military force, disarming of irregular military formations, and patrolling the lines of demarcation.

The other point which led this operation to a success, and often forgotten when there is an analysis of the achievements of a peacekeeping operation, the existence of a serious political will in supporting the forces on the ground.

Finally, a politically-minded observation. The role of London, Stockholm and St. Petersburg, even if appearing as neutral, in reality, none of these were “honest brokers,” given their political interests and/or strategic imperatives; and these kinds of dynamics should be analyzed for a proper interpretation of third parties in international crisis.

Enrico Magnani, PhD is a UN officer who specializes in military history, politico-military affairs, peacekeeping and stability operations. (The opinions expressed by the author do not necessarily reflect those of the United Nations). This paper was presented at the 53rd Conference of the Consortium of the Revolutionary Era, Fort Worth, Texas, USA, 2-4 February 2023.

Featured: Danish Soldiers Returning to Copenhagen, by Otto Bache; painted in 1894.