The consequent American Civil War, beginning in 1861, led to the end of chattel slavery in America. Not long after the war broke out, through a legal maneuver credited to Union General Benjamin F. Butler, a lawyer by profession, slaves who came into Union "possession" were considered "contraband of war". General Butler ruled that they were not subject to return to Confederate owners as they had been before the war. Soon word spread, and many slaves sought refuge in Union territory, desiring to be declared "contraband." Many of the "contrabands" joined the Union Army as workers or troops, forming entire regiments of the U.S. Colored Troops. Others went to refugee camps such as the Grand Contraband Camp near Fort Monroe or fled to northern cities. General Butler's interpretation was reinforced when Congress passed the Confiscation Act of 1861, which declared that any property used by the Confederate military, including slaves, could be confiscated by Union forces.