On Nov. 1, 1864, the Maryland General Assembly banned slavery. At the time, Baltimore had one of the largest populations of free blacks. But some of the 53 slaves at Sotterley Plantation in St. Mary’s County chose to stay after being freed. Our guests: Joanne Martin, founder of Baltimore’s National Great Blacks in Wax Museum; Andrew Diemer, assistant professor at Towson University and historian of slavery in the Mid-Atlantic; and Jeanne Pirtle, Sotterley’s education director.