From the National Cathedral service, 2017
Although the exact origins of Memorial Day are disputed, the first observance of Memorial Day is thought to have taken place in April 1865, when a group of former slaves gathered at a Charleston, SC horse track turned Confederate prison where more than 250 Union soldiers had died. The bodies of soldiers buried in a mass grave were reinterred in individual graves on the site. On May 1, 1865, some 10,000 black Charleston residents, white missionaries, teachers, schoolchildren and Union troops marched around the Planters’ Race Course, singing and carrying armfuls of roses.