London Protocol
On 8 May 1852, after the First War of Schleswig, an agreement called the London Protocol was signed. This international treaty was the revision of an earlier protocol, which had been ratified on 2 August 1850, by the major Germanic powers of Austria and Prussia. The second London Protocol was recognised by the five major European powers—Austria, France, Prussia, Russia, and the United Kingdom—as well as by the Baltic Sea powers of Denmark and Sweden.