Frederick VI of Denmark
The Treaty of Kiel was signed by the United Kindom and Sweden on one side, and the Kindoms of Denmark and Norway on the other one, on January 14th, 1814 in Kiel, capital of the German State of Schleswig-Holstein.
George III of the United Kindom of Great Britain
The Treaty put an end to the hostilities due to Napoleonic Wars, where Britain and Sweden were allies within the Sixth Coalition against France, whereas Denmark-Norway was allied of Napoleon Bonaparte.
Charles XIII of Sweden
Denmark lost Norway for good, after having ruled it for almost 400 years.