After the Napoleonic Wars, Saxe-Lauenburg was restored as a Hanoverian dominium in 1813. The Congress of Vienna established Saxe-Lauenburg as a member state of the German Confederation. In 1814 the Kingdom of Hanover bartered Saxe-Lauenburg against Prussian East Frisia. On 7 June 1815, after 14 months under its rule, the Prussia granted Saxe-Lauenburg to Sweden, receiving in return the former Swedish Pomerania, however, additionally paying 2.6 million Taler to Denmark, in order to compensate Denmark for the loss of Norway. Denmark gained that ducal territory north of the Elbe, now ruled in personal union by the Danish House of Oldenburg, from Sweden, which thus again compensated Danish claims to Swedish Pomerania. On 6 December 1815 Frederick VI of Denmark issued his "Asseveration Act" (Versicherungsacte) affirming the given laws, the constitution and the Ritter- und Landschaft of Saxe-Lauenburg. In 1816 his administration took possession of the duchy.