The 1852 London Protocol settled Danish succession and territorial integrity after the First Schleswig War, directly triggering the German-Danish War of 1864.
Key Facts
- Signing date
- 8 May 1852
- Signatory powers
- Austria, France, Prussia, Russia, United Kingdom, Denmark, Sweden
- Chosen successor
- Prince Christian of Schleswig-Holstein-Sonderburg-Glücksburg
- Danish Law of Succession enacted
- 31 July 1853
- Years until war triggered
- 11 years
- Earlier protocol ratified
- 2 August 1850
By the Numbers
Location
Cause → Event → Consequence
The First War of Schleswig left unresolved questions about the constitutional relationship between the Kingdom of Denmark and the duchies of Schleswig, Holstein, and Lauenburg. Frederick VII of Denmark was childless, creating an imminent dynastic crisis because the lines of succession for Denmark and the German duchies diverged, threatening the unity of the Danish federation.
On 8 May 1852, seven European and Baltic powers signed the London Protocol, affirming Denmark's territorial integrity as a 'European necessity.' The treaty joined the duchies of Schleswig, Holstein, and Lauenburg to Denmark by personal union, modified the ducal line of succession, and designated Prince Christian of Glücksburg as second-in-line to the Danish throne, partly to protect the strategic port of Kiel from Prussian control.
The Protocol was implemented by Denmark's Royal Ordinance of 31 July 1853, granting Prince Christian and his family Danish royal titles. Eleven years later, Prussia and Austria declared Denmark in violation of the Protocol after Christian IX signed the November Constitution of 1863, precipitating the German-Danish War of 1864. Following defeat, Kiel was transferred to Prussian control in 1867.
Political Outcome
The Protocol affirmed Danish territorial integrity, settled the line of succession in favor of Prince Christian of Glücksburg, and stipulated that Schleswig would have no greater constitutional affinity to Denmark than Holstein.
Disputed status of Schleswig-Holstein duchies and uncertain Danish succession following First War of Schleswig
Danish federation affirmed; Prince Christian of Glücksburg designated heir, stabilizing succession under great-power guarantee