First Army Corps (Spanish–American War)
The First Army Corps was a unit of the United States Army raised for the Spanish–American War. As relations between Spain and the United States deteriorated in the spring of 1898, the leaders of the U.S. Army began to plan for its first large-scale campaign since the Civil War, which had ended more than 30 years previously.
Source: Wikipedia — First Army Corps (Spanish–American War) (CC BY-SA 4.0)