In 1897 Admiral Alfred von Tirpitz, state secretary of the German Imperial Naval Office devised his initially rather practical, yet nonetheless ambitious plan to build a sizeable naval force. Although basically posing only an indirect threat as a Fleet in being, Tirpitz theorized, that its mere existence would force Great Britain, dependend on unrestricted movement on the seas, to agree to diplomatic compromises. Tirpitz started the program of warship construction in 1898 and enjoyed the full support of Kaiser Wilhelm. Wilhelm entertained less rational ideas on the fleet, that circled around his romantic childhood dream to have a "fleet of own some day" and his obsessive adherence to direct his policies along the line of Alfred Thayer Mahan's work The Influence of Sea Power upon History. In exchange for the eastern African island of Zanzibar, Germany had bargained the island of Heligoland in the German Bight with Britain in 1890, and converted the island into a naval base and installed immense coastal defense batteries. Britain considered the imperial German endeavours to be a dangerous infringement on the century-old delicate balance of global affairs and trade on the seas under British control. The British, however, resolved to keep up the naval arms race and introduced the highly advanced new "Dreadnought" battleship concept in 1907. Germany quickly adopted the concept and by 1910 the arms race again escalated.