In the context of this artwork, explain the Pre-emancipation of the Composition.
Mary Bowser, former enslaved Union spy during the Civil War
William Harvey Carney, soldier and formerly enslaved
Gabriel, enslaved blacksmith and rebellion leader
Dred Scott, enslaved man and plaintiff of Dred Scott v. Sandford
Nat Turner, enslaved preacher and rebellion leader
Nat Turner Mary Bowser plaintiff Civil War William Harvey Carney Union Gabriel emancipation Dred Scott v. Sandford Dred Scott