American Expeditionary Force
The American Expeditionary Force was the official name given to the United States military that took part in World War I, under the command of General John J. Pershing. During World War I, the AEF, as the American Expeditionary Force came to be known, fought alongside British and French troops in the trenches from its slow arrival in mid-1917 through the Armistice of November 11, 1918.
The United States was a reluctant participant in the First World War. Despite such provocation as the sinking of the Lusitania in 1915, President Wilson campaigned for re-election in 1916 largely on the basis that he had kept the United States out of what many believed to be a European war. Unrestricted submarine warfare by Germany eventually led Wilson to declare war in April 1917. The following month, Wilson appointed Major General John J. "Black Jack" Pershing to command the American Expeditionary Force. However, Pershing insisted that his men be well trained, and therefore total numbers of American soldiers in Europe remained low until 1918.
The American Expeditionary Force first reached the front in late October 1917. Its first major victory was at the Battle of Cantigny in May 1918, and its most notable action took place at Belleau Woods in June of that year. Both Army and Marine units of the American Expeditionary Force were instrumental in stopping German advances towards Paris, before victory in the Meuse-Argonne offensive, which ended the war.