Iron Brigade and was previously called the "Black Hat" Brigade. The 3rd Brigade Combat Team, 1st Infantry Division was known as the Iron Brigade from its formation in 1917 through World War I, World War II and Vietnam, until some time in the early 2000s when, for reasons that are still unclear, the name was changed to Duke Brigade. The unit crest was an Iron Cross in a triangle, it appears that that was also changed. The 3rd Brigade of the 4th Infantry Division is also known as the Iron Brigade. Its unit crest is similar to the medals issued to veterans
Battle of the Iron Triangle Phú Cường, the capital of Bình Dương Province, was an important industrial and farming center and contained the ARVN Engineer School. It was linked by a major highway with the large ARVN Phu Loi Base Camp and, farther east, with Bien Hoa Air Base. Lying as it did in the center of the Saigon River corridor, at the junction of Highways 13 and 1, and only 16km from the outskirts of Saigon, Phú Cường was vital to the defense of Saigon. The terrain within the Iron Triangle was flat, almost featureless, and covered by dense brush and undergrowth. The clearings,