Butler declared the slaves contraband of war and allowed them to remain with the Union Army .
General Benjamin Butler set a precedent for Union forces on May 24 , 1861 , when he refused to surrender escaped slaves to Confederates claiming ownership .
General declared the slaves contraband of war and allowed them to remain with the Union Army .
General Benjamin Butler set a precedent for Union forces on May 24 , 1861 , when he refused to surrender escaped slaves to Confederates claiming ownership .