The division was activated in December 1917 and sent to France; however, the troops never fought together as a division, and in fact, the provisional division headquarters was demobilized in May 1918. Over the objections of the division's commander, Brig. Gen. Roy Hoffman (appointed 15 December 1917), its brigades were broken up and the regiments brigaded with French Army formations. They were issued French equipment and arms but wore US uniforms; the "blue hat" nickname is derived from the blue-painted "Casque Adrian" helmets they wore.