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. 20 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 Danesinsisted 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,