On this spot, on July 6th, 1863, in front of Hagerstown City Hall, Captain Ulrich Dahlgren, son of Admiral John Dahlgren, inventor of the Dahlgren Gun, was seriously wounded, leading to the loss of a leg. After the war his widowed mother Madeline, purchased the inn at Turner’s Gap, atop South Mt. and built the Dahlgren Chapel in honor of her son and husband.The action occurred on the Confederate retreat from Gettysburg.