"Dracula" (1897) also tapped into English fears of foreign forces arriving unopposed on its shores, although between 1870 and 1903 the majority of these works assumed that the enemy would be France, rather than Germany. This changed with the publication of Erskine Childers's 1903 novel "The Riddle of the Sands". Often called the first modern spy novel, two men on a sailing holiday thwart a German invasion of England when they discover a secret fleet of invasion barges assembling on the German coast. Of these hundreds of authors, few are in print now. Saki is one of the exceptions, although his 1913 novel "When William Came" (subtitled "A Story of London Under the Hohenzollerns") is more jingoistic than literary. Another is John Buchan, whose novel "The Thirty-Nine Steps", published in 1915 but written just prior to the outbreak of World War I, is a thriller dealing with German agents in Britain preparing for an invasion.