XII Corps (United States)

XII Corps
Shoulder sleeve insignia of XII Corps
Active	1942–45
Country	United States
Branch	United States Army
Size	Corps
Part of	Third United States Army
Engagements	World War II
Commanders
Notable commanders	Manton S. Eddy Stafford LeRoy Irwin

The XII Corps fought from northern France to Austria in World War II. Constituted in the Organized Reserves in 1933, it was activated on 29 August 1942 at Columbia, South Carolina. XII Corps became operational in France as part of Lieutenant General George S. Patton's Third Army on 1 August 1944. Initially commanded by Major General Gilbert R. Cook, bad health forced MG Cook to relinquish command to Major General Manton S. Eddy within three weeks. MG Eddy commanded the corps until late April 1945, when his own health problems forced him to turn over command to MG Stafford LeRoy Irwin.

Assembling south of Le Mans on 13 August 1944, XII Corps began driving eastward and liberated the cities of Orléans and Châteaudun within five days. Moving rapidly against disorganized German resistance, the corps rapidly took Sens, Montargis, Troyes, Châlons-sur-Marne, and Vitry-le-François. By 31 August 1944, XII Corps had seized a bridgehead over the Meuse River at Commercy in Lorraine.

At the beginning of September 1944, serious gasoline shortages forced an abrupt halt to General Patton's pursuit across northern France. Resuming its advance on 4 September, but facing shortages of gasoline and ammunition because of the allied logistical crisis, XII Corps now confronted a vastly changed tactical situation. A combination of German reinforcements and regained cohesion in the German forces (Fifth Panzer Army) confronting the U.S. Third Army resulted in dramatically increased German resistance in the region of Metz and Nancy in the Moselle River valley. From the German point of view, Lorraine (German: Lothringen) was seen as part of Germany and would be defended with bitter determination.