On January 27, 1777, Deborah Norris wrote to her friend Sally Wister of a "shocking sight." Large pits are dug in the negroes burying ground (Washington Square), and forty or fifty (soldiers) coffins are put in the same hole.
Throughout that winter, disease thinned the ranks of the American army. John Adams, a member of the Continental Congress meeting in Independence Hall, visited the Square in April 1777. He spent an hour "in the congregation of the dead." The graves of the soldiers, perhaps 2,000 he had been told, "are enough to make the heart of stone melt away."
During the British occupation later that year, American captives died every day. Their bodies were dragged into carts, hauled here and dumped into the earth.
Only after yellow fever ravaged Philadelphia in 1793, did burials in the Square stop. Some believed that graves emitted miasmas, vapors suspected as sources of epidemics.