The American Expeditionary Forces (AEF) were the US military forces sent to Europe in the First World War.
The AEF fought along with allied forces against the troops of the German Empire. They helped France to defend the Western Front during the Aisne Offensive in May 1918, and they had their most important fight in the Meuse-Argonne offensive in the autumn of 1918.
The president of the United States, Woodrow Wilson, initially planned to give the command of the AEF to General Frederick Funston, but after the sudden death of the latter, Wilson appointed General John J. "Black Jack" Pershing in May 1917, at that time in charge of supervising the US forces during the course of the war.
Pershing insisted that American soldiers be trained before going to Europe. As a result, few troops were sent in 1918. Pershing insisted that US forces would not be destined simply to fill gaps in the French and United Kingdom troops, and resisted European efforts to have those troops to replace the fallen allies. This attitude caused resentment in the allied leaders, who at this point suffered from lack of troops.
By June 1917, there were 14,000 American soldiers in France and until May of the following year this figure rose to one million. Since the transport ships needed to bring US troops to Europe were scarce, the US Navy also provided transport ships and defense cruisers with which soldiers from New York, New Jersey and Virginia were transported. The mobilization effort put the resources of the US Navy to the limit and required new strategies of organization and command structures to allow the rapid and efficient transportation of such a large number of troops and supplies.
The first troops of the AEF to reach Europe were called "Doughboys" by other allied troops, and arrived in June 1917. However, they did not directly participate in the combat front until October, when the 1st Infantry Division of The USA, one of the best trained divisions of the AEF, entered the trenches, in Nancy.
Pershing wanted the AEF to operate independently of the other allied forces, but this could not be done until they were adequately trained and the necessary supplies arrived in Europe. The training schools in the United States sent their best men to the front, and Pershing established training places in France.
From 1917 to 1918 the US divisions were usually employed to reinforce the French and British troops who defended their lines and made surprise attacks against the German positions. With the first American victory in Cantigny at the beginning of May 1918, the commanders of the AEF increased their independence in the control of the forces. By July 1918, French forces were assigned to reinforce the operations of the AEF.
During the Battle of Saint-Mihiel, on September 12, 1918 Pershing commanded the 1st US Army, which comprised seven divisions and more than 500,000 men in the largest offensive operation carried out by the United States. This successful offensive was followed by the Meuse-Argonne offensive, from September 16 to November 11, 1918, in which Pershing commanded more than one million American and French soldiers. Through these two military operations, the allies recovered more than 520 km² of French territory occupied by the German forces. When the Armistice suspended the fighting on November 11, 1918, the US Expeditionary Forces had become a modern unit with combat experience.