unted in their millions compared with the hundreds of thousands of half a century earlier. The essential causes of World War I were the attitude of intense nationalism that permeated Europe throughout the 19th and into the 20th century, the political and economic rivalry among the nations, and the establishment and maintenance in Europe after 1871 of large armaments and of two hostile military alliances.The French Revolution and the Napoleonic era had spread throughout most of Europe the idea of political democracy, with the resulting idea that the people of the same ethnic origin, language, and political ideals had the right to independent states. The principle of national self - determination, however, was largely ignored by the dynastic and retrogressive forces that dominated in the settlement of European affairs at the Congress of Vienna in 1815. Several peoples who desired national independence were made subject to local dynasts or to other nations. Notable examples were the German people, whom the Congress of Vienna left divided into numerous duchies, principalities, and kingdoms. Italy, also left divided into many parts, some of which were under foreign control; and the Flemish - and French - speaking Belgians of the Austrian Netherlands, whom the congress placed under Dutch rule. Revolutions and strong nationalistic movements during the 19th century succeeded in canceling much of the retrogressive and antinationalist work of the congress. Belgium won its independence from the Netherlands in 1830, the unification of Italy was accomplished in 1861, and that of Germany in 1871. At the close of the century, however, the problem of nationalism was still unresolved in other areas of Europe, resulting in tensions both within the regions involved and between various European nations. One particularly noticeable nationalistic movement, Panslavism, figured heavily in the events preceding the war.The attitude of nationalism was also visibl...
