In the winter of 1863, Schleswig-Holstein was in the news again. Frederick VII of Denmark had died on 15 November 1863, triggering a succession crisis. As there was no direct male heir (the Danish Crown passed instead via the maternal line to Christian of Glücksburg), a dispute arose over who had a legitimate hereditary claim to rule over the duchies. The details of the Schleswig-Holstein controversy have always been taxing to follow – the more so as nearly everyone involved in it was called either Frederick or Christian – and the following is a sketch of the salient points. A series of international treaties had established in the early 1850s that the new King of Denmark, Christian of Glücksburg, would succeed on the same terms as his predecessor, Frederick VII. In 1863, however, the waters were muddied by the appearance of a rival claimant, Prince Frederick of Augustenburg. The Augustenburgs did have a longstanding claim to the duchies, but Prince Frederick’s father, Christian of Augustenburg, had agreed to renounce it as part of the 1852 Treaty of London. In 1863, however, Frederick of Augustenburg declared himself unbound by the treaty of 1852 and defiantly adopted the title ‘Duke of Schleswig-Holstein’. His claim was enthusiastically supported by the German nationalist movement.
It is worth reflecting for a moment on the distinctive quality of the Schleswig-Holstein crisis. Modern and pre-modern themes were interwoven. On the one hand, it was an old-fashioned dynastic crisis, triggered, like so many seventeenth and eighteenth-century crises, by the death of a king without male issue. In this sense, we might call the conflict of 1864 ‘the War of the Danish Succession’. On the other hand, Schleswig-Holstein became the flashpoint for a major war only because of the role played by nationalism as a mass movement. The galvanizing effect of the Schleswig-Holstein issue on the German national movement had already made itself felt in the Frankfurt Parliament of 1848; in 1863–4, German nationalist opinion demanded that the duchies be constituted jointly as a new German federal state under the rule of the Augustenburg dynasty. Nationalism was crucial on the Danish side as well: the Danish nationalist movement demanded that Denmark defend its claim to Schleswig, and it was supported in this by the mainstream of Danish liberal opinion. The inexperienced and ineffectual new king, Christian IX, thus faced an explosive domestic situation when he came to the throne. At one point, the demonstrations taking place outside the royal palace in Copenhagen were so turbulent that the city’s chief of police warned of the imminent collapse of law and order in the capital. It was anxiety about the prospect of political upheaval that forced the hand of the new king. By signing the November Constitution of 1863, Christian IX announced his intention to absorb the Duchy of Schleswig into the Danish unitary state, a gesture denounced by the German nationalists as an unpardonable provocation.
There were now three conflicting positions on the duchies. The Danes insisted on the incorporation of Schleswig as set out in the November Constitution of 1863. The German nationalist movement and the majority of states in the Confederation favoured the Augustenburg claim and were prepared to support an armed intervention. The Prussians and the Austrians opposed the Augustenburg claim and insisted that the Danes (and the Augustenburgs) abide by the promises made in the international treaties of 1850 and 1852. After much horse-trading at the Confederal Diet in December, a resolution was passed (by just one vote) that an intervention could proceed on the basis of the London treaties. On 23 December 1863, a small Confederal task force crossed the Danish frontier and moved northwards without resistance to occupy most of Holstein south of the river Eider. The strains within the Confederation soon began to tell. The task force (with only 12,000 men) had been sufficient to take undefended Holstein, but Schleswig would be another matter. The Danes were expected to put up a vigorous defence and a much larger force would be required to ensure success. Still acting in concert, Prussia and Austria declared that they were prepared to invade Schleswig, but only in their own right as European powers and only on the basis of the treaties of 1851 and 1852, not as representatives of the German Confederation and not in support of the Augustenburg claim. In January 1864, the two powers presented their joint ultimatum separately to Denmark (without consulting the other Confederal states) and, when the Danes refused to comply, moved their combined forces across the river Eider and into Schleswig.
It was a remarkable turnaround. The Austro-Prussian rivalry of the 1850s and early 1860s seemed to have made way for a mood of sweet harmony and cooperation. But the apparent unity of purpose concealed a pandemonium of conflicting expectations. For the Austrian Chancellor Count Johann Bernhard Rechberg, the joint campaign was a chance to discredit the German nationalist movement while establishing an Austro-Prussian condominium over Germany and reinvigorating the trans-territorial institutions of the German Confederation. It was also a way of preventing Berlin from securing major unilateral gains (such as the annexation of Schleswig) at Denmark’s (and Austria’s) expense. At the back of Rechberg’s mind was another threatening prospect: Napoleon III, who had begun to warm to his role as Europe’s troublemaker, had suggested to the Prussians that France would support the outright annexation of Schleswig-Holstein, along with the lesser states of northern Germany, to Prussia. It looked as if Paris was angling for another anti-Austrian war, with Prussia playing the role of Piedmont. Rechberg, who was kept fully informed by Bismarck of these initiatives, knew this was a war that the Austrian Empire could not afford to fight.
Bismarck’s agenda could scarcely have been more different. The Confederation as such played no role in his planning. His ultimate objective was to annex the duchies to Prussia. The Prussian Chief of Staff Helmut von Moltke may well have been the key influence here. Moltke was strongly opposed to the transformation of the duchies into an independent principality, on the grounds that the new entity might become a satellite of the Habsburgs and open up a hole in Prussia’s northern seaward flank. As Bismarck knew, however, a unilateral annexation would have exposed Prussia to the threat of combined reprisals from Austria, the rest of the Confederation, and possibly one or more European powers. The extra troops would also come in handy, especially if, as Moltke warned, the Danes succeeded in exploiting their superiority at sea to evacuate their troops from the mainland. The agreement to work with Austria was thus a temporary device to limit risk and ensure that all options remained open.
The Danish war came to an end on 1 August 1864, when the Danes were forced to sue for peace. Three features of the conflict deserve emphasis. The first is that the Prussians did not outperform the Austrians militarily. One early mistake was to nominate the Prussian Field Marshal Count Friedrich Heinrich Ernst von Wrangel as overall commander of the allied forces. The eighty-year-old Wrangel was old for his years and, though popular with the conservatives at court, at best a mediocre general. All his combat experience had been acquired against civilian insurgents in the revolutions of 1848. While Wrangel lurched from blunder to blunder in Denmark, the Austrian units acquitted themselves with courage and skill. On 2 February 1864, one Austrian brigade charged and took the Danish positions at Ober-Selk with such panache that old Wrangel rushed to embrace and kiss its commander on the cheeks, to the embarrassment of his Prussian colleagues. Four days later, the Austrian Brigade Nostitz broke through heavily defended Danish fortifications at Oeversee, while a Prussian Guards division on their flank looked on almost inert. These were frustrating setbacks for an army that had not experienced war for half a century and desperately needed to prove its mettle, both to the international community and to a domestic population that had been following the political struggle over military reform.
A second striking feature of the conflict was the primacy of the political over the military leadership. The Danish war was the first Prussian armed conflict in which a civilian politician exercised control. Throughout the war Bismarck ensured that the evolution of the conflict served the objectives of his diplomacy. He prevented the Prussian forces from pursuing the Danish army into Jutland during the early weeks of the war, so as to reassure the great powers that the joint campaign was not aimed at the territorial integrity of the Danish kingdom. There were slip-ups, to be sure – in mid-February, Wrangel sent an advance detachment of Guards north of the Jutland border despite instructions to the contrary. But Bismarck persuaded the war minister to send a sharp reprimand to the elderly general, and Wrangel was relieved of his command at Bismarck’s insistence in mid-May. It was Bismarck who oversaw Prussian communications with Vienna, ensuring that the terms of the alliance evolved to Prussia’s advantage. And in April it was Bismarck who insisted that the Prussian forces attack the Danish fortifications at Düppel in Schleswig, rather than mounting a protracted invasion of Denmark that might have dragged the other powers into the conflict.
The decision to attack Düppel was controversial. The Danish positions there were heavily fortified and manned, and it was clear that a Prussian frontal attack would succeed only – if at all – with numerous casualties. ‘Is it supposed to be a political necessity to take the bulwarks?’ asked Prince Frederick Charles, a brother of the king, who had been placed in charge of the siege. ‘It will cost a lot of men and money. I don’t see the military necessity.’ The case for engineering a showdown at Düppel was indeed political rather than military. A full-blown invasion of Denmark was undesirable for diplomatic reasons and the Prussians sorely needed a spectacular victory. There was much grumbling among the commanders, but Bismarck’s will prevailed and the deed was done. On 2 April, the Prussians began a heavy bombardment of the defence works, using their new rifled field guns. On 18 April, the infantry went in under the command of Frederick Charles. It was no easy fight. The Danes offered fierce resistance from behind their battered defences and subjected the Prussians to heavy fire as they climbed the slopes before the entrenchments. Over 1,000 Prussians were killed or wounded; the Danes suffered 1,700 casualties.
Bismarck’s dominance throughout the conflict generated considerable tension and ill-feeling. When the commanders protested, Bismarck was quick to remind them that the army had no business interfering in the conduct of politics – itself an extraordinary declaration in the Prussian setting, and one which reveals how things had changed since the revolutions of 1848. The army, however, had no intention of accepting this verdict, as War Minister Albrecht von Roon made clear in a memorandum of 29 May 1864:
There has been, and is now hardly any army that regarded itself and understood itself to be purely a political instrument, a lancet for the diplomatic surgeon. [… ] When a government depends – and this is our situation – particularly upon the armed part of the population [… ] the army’s views on what the government does and does not do are surely not a matter of indifference.
In the exhilaration of victory, these altercations were quickly forgotten, but the issue underlying them would later resurface in more acrimonious and menacing forms. Bismarck’s assertion of control over virtually every branch of the executive papered over but did not solve the structural problem of civil–military relations at the apex of the Prussian state. The 1848 revolutions had parliamentarized the monarchy without demilitarizing it. At the heart of the post-revolutionary settlement lay an avoided decision that would haunt Prussian (and German) politics until the collapse of the Hohenzollern monarchy in 1918.
Prussia’s victories in Denmark – Düppel was followed at the end of June by a successful amphibious assault on the island of Alsen – also transformed the domestic political landscape. The resulting wave of patriotic enthusiasm opened up latent divisions within the Prussian liberal movement. The Arnim-Boitzenburg petition of May 1864, which called for annexation of the duchies, attracted 70,000 signatures, not only from conservatives but from many liberals as well. Prussian military successes also had an unsettling effect more generally, since they seemed to demonstrate the effectiveness of the reform programme so bitterly opposed by the liberals. There was a growing desire for a settlement with the government, reinforced by the fear that if the conflict dragged on, the liberal movement would forfeit its purchase on public opinion.
During 1864 and 1865, Bismarck and ‘his’ ministers played skilfully with the parliament, confronting it with bills that divided the liberal majority or forcing it into unpopular positions. In the naval construction bill of 1865, for example, the government asked parliament to approve the building of two armed frigates and a naval base in Kiel, at a cost of just under 20 million thalers. The creation of a German navy was a fetish to the liberal nationalist movement, especially in the aftermath of the Danish war, where naval operations had played a prominent role. The overwhelming majority of the deputies strongly supported the proposed expenditures, but they were forced nevertheless to reject the bill on the grounds that, in the absence of a legal budget, no new funds could be approved by parliament. Bismarck seized his opportunity to deliver a tirade against the ‘impotently negative’ attitude of the chamber.