Though wars with Germany would become a central issue for Britain for much of the 20th century, few Britons anticipated that before 1900. Historically, it was France which was the traditional enemy of England and Britain, from the Hundred Years' War until the Napoleonic Wars. Just nine years before "The Riddle of the Sands", William Le Queux published "The Great War in England", raising the specter of a French surprise invasion of England, reaching London – with Germany cast as Britain's loyal ally, rushing to help and in the nick of time saving England from the evil French; as evident from the great success of this book when published in 1894, the British public at that time took seriously the idea of a French threat and a German ally. But Emperor Wilhelm II's policy of building up the German Navy and challenging the British sea power effected a change in the actual power relations - reflected in the specific literary genre of invasion novels and the identity assigned to the possible invader of British soil.