Origins of Hoorah

You can hear it echoing from the hallowed halls of Fort Benning, Ga.'s Infantry Center to the ranges at Fort Lewis, Wash. It is uttered at award ceremonies, bellowed from formations, and repeated before, during and after training missions. You can hear it shouted by Air Force Security Forces, Pararescue, and Combat Controllers. The word is thundered out by Navy SEALs, and by United States Marines (who pronounce it OohRah!). So, where did the term originate?