BACKGROUND: When the U.S. Army deployed to France in 1917 they wore the M1912 service cap but soon found that it was completely inadequate for the conditions found on the battlefield. The solution was found with the allied armies fighting along side of them in the form of a simple rectangular side cap based on a style worn by the French. The cap, which was adopted in 1917, became known as the "overseas" cap because it was only issued to U.S. forces serving in Europe. It was removed from service in 1919 but gradually slipped back into wear through its unofficial adoption by various branches. The cap was approved for use Army wide by the time WW2 broke out.