Although O'Neill wrote the tragic Beyond the Horizon in 1918, it features no reference to the biggest tragedy of the time, World War I, which ended the same year. This may be because O'Neill intended his story to take place in the years before World War I started. Or, it may be because the play features enough tragedy without mentioning the war. In any case, farmers and some merchant seamen - two occupations represented in the play by the Mayo brothers - were greatly affected by the war.

Even before the United States officially entered the war in 1917, American farms were helping to provide food supplies to the Allied forces. These exports, along with the exportation of munitions, helped aid the war effort and led to greater economic prosperity in the United States during the first few years of the war. As J. M. Roberts notes in...