As the Napoleonic Wars came to a close, allied Sweden attacked pro-French Denmark. Forced to come to terms, the Danes signed the Treaty of Kiel in early 1814, agreeing to cede Norway to Sweden. However, Denmark was allowed to retain the historically Norwegian territories of Iceland, the Faroe Islands, and Greenland.
In June 1812 the United States, angered by the Royal Navy’s impressment of Americans and its naval blockade during the Napoleonic Wars, declared war on Britain. Preoccupied with the war in Europe, the British stayed largely on the defensive until the defeat of France in 1814 allowed them to deploy more troops to North America and launch an offensive which saw the burning of Washington. These actions, as well as the end of the Royal Navy’s wartime practises which had triggered the war, persuaded the US to come to terms and the two sides agreed to a return to the per-war status quo.in wikipedia
In late 1813 allied Swedish and German forces invaded the Danish duchies of Schleswig and Holstein, forcing Denmark to sue for peace. By the two treaties of Kiel, signed 14 January 1814, Denmark ended its alliance with Napoleon and agreed to cede Heligoland to the British and Norway to Sweden. In return Sweden agreed to give Swedish Pomerania to Denmark. Denmark retained control of the historically Norwegian territories of Iceland, Greenland, and the Faroe Islands.in wikipedia