Boston's first African residents arrived as slaves in 1638 with early colonists. Over time, more of their descendants were born free to white mothers; in other cases slaveholders freed slaves for service. After the American Revolutionary War, Massachusetts effectively abolished slavery by the terms of its new constitution. By the 1790 census, no slaves were recorded in Massachusetts. African Americans became activists in the abolition movement, also working to gain racial equality and educational parity with whites. They engaged in political processes to meet their objectives.