In August of 1758, in Spotsylvania County, Virginia, a poor Irish immigrant named Mary Madden bore a child, Sarah Madden, whose father was said to be a slave and the property of Colonel James Madison, father of the future president of the United States. This daughter, though born a free mulatto, became indentured to the Madisons. There she worked as a seamstress to pay off the fine of her birth until she was 31 years old.

Sarah Madden bore ten children and when the term of her indenture was over, she and her youngest son, Willis, struck out for themselves--Sarah as a seamstress, laundress,...