Jutland peninsula is made up of the German Bundesland of Schleswig-Holstein. Schleswig-Holstein has two parts: the former duchies of Schleswig (Danish fief) and Holstein (German fief), both of which have passed back and forth between Danish and German rulers several times. The last adjustment of the Danish–German border followed the Schleswig Plebiscites in 1920 and resulted in Denmark's regaining Northern Schleswig ( or more commonly today: "Sønderjylland"). The historical southern border of Jutland are areas south of Kiel, Husum and Rendsburg, but the river Eider was the border between the former duchies of Schleswig and Holstein, as well as the historical
Battle of Jutland third fleet action between steel battleships, following the smaller but more decisive battles of the Yellow Sea (1904) and Tsushima (1905) during the Russo-Japanese War. Jutland was the last major battle in world history fought primarily by battleships. Germany's High Seas Fleet intended to lure out, trap, and destroy a portion of the Grand Fleet, as the German naval force was insufficient to openly engage the entire British fleet. This formed part of a larger strategy to break the British blockade of Germany and to allow German naval vessels access to the Atlantic. Meanwhile, Great Britain's Royal Navy pursued a