St. Peter’s Roman Catholic Church in Harpers Ferry flew a British flag to avoid destruction during the conflict

Father Michael Costello, the pastor of St. Peter's Roman Catholic Church, flew the British flag over the building to protect it from numerous artillery bombardments and battles for the town during the Civil War.

St. Peter's was spared due to its alleged British affiliation despite the crippling damage other neighboring structures endured during the Battle of Harpers Ferry and subsequent artillery bombardments in the summers of 1863 and 1864. St. Peter's was regularly used as a temporary hospital because it was still standing during the war, and Costello continued to conduct services and give sacraments there. The only church in Harpers Ferry that had not been badly damaged or destroyed by Northern or Southern soldiers was St. Peter's.