Gen. Martin E. Dempsey joins New York National Guard's "Fighting 69th" Infantry Regiment on St. Patrick's Day at their armory in New York City, March 17, 2015. It was their ferocity at the Civil War battle in Fredericksburg that led to their nickname, coined by Confederate Gen. Robert E. Lee, "The Fighting 69th." (DOD photo by D. Myles Cullen/Released)