Short Term Cause: Alliances Alliances create situations for war and rivals. Additionally, if a country join the war, its alliance also joins. Short Term Cause: Rise of military The rise of militarism increases the World War I began in June of 1914, and is considered to have five major causes that led to the outbreak of the war. By the end of the war, over 17 million people had been killed, including over 100,000 American troops. What were the long-term and short-term causes of World War I? Long-term causes of war On 28 June 1914, a Serbian shot an Austrian. Within six weeks, many of the countries of Europe had become involved in a war that was to cause the deaths of 10 million soldiers. World War I began in June of 1914, and is considered to have five major causes that led to the outbreak of the war. World War I, known as the "war to end all wars," occurred between July 1914 and November 11, 1918. These five causes include the four long-term causes (militarism, alliances, imperialism and nationalism) discussed in this reading and one short-term cause (the assassination of Franz Ferdinand).