CROWNSVILLE, MARYLAND—While looking for the French general Comte de Rochambeau’s 1781 campsite at Belvoir, the plantation home of Francis Scott Key’s grandmother, archaeologists found the brick floor of a large building that may have served as a dormitory-style slave quarters. “The discovery of this is an amazing contribution to understanding African-American life in Anne Arundel County. Up to this point, we did not know they were building slave barracks like this,” county cultural resources planner Jane Cox told The Capital Gazette. The building’s footprint is more than twice the size of most slave quarters. “The foundation of this thing is so massive, we strongly suspect it had two stories,” said county archaeologist All Luckenbach.