Even their future children's freedom.
In 1681, Nell -- she was born Eleanor Butler -- was a 16-year- old indentured servant, a white woman working as a laundress in Maryland for the third Lord Baltimore. One day, she told her employer that she planned to wed the man identified in court records as "Negro Charles."
"Lord Baltimore told her what would happen and warned her not to do it," says Agnes Kane Callum, a direct descendant of the couple. "She didn't listen. They were married by a Catholic priest. They had seven or eight children. The whole family was the property of Charles' master."
That's just one of the fascinating stories that Callum, 80, unearthed while painstakingly preparing her family's genealogical chart, on display in the Lewis Museum's permanent collection.
Callum, a Baltimorean, began preparing the chart in 1968 while taking a black history course at
The course introduced her to genealogy, one of the consuming passions of her life. She spent decades tracing her family on her mother's side to 1681, and her family on her father's side to 1793.
"I never thought it would go this far," she says.
In the early 1970s, Callum, then over 50, was named a Fulbright Scholar and spent a year studying in Ghana. She is about to publish the 25th annual issue of the black genealogical journal she started in 1982, Flower of the Forrest. And she is at work on her 10th book of history and genealogy.
She has a seemingly endless supply of powerful anecdotes, including the one about another former slave ancestor who was sold at auction at Howard and Fayette streets in 1835.
But a favorite remains the story of Nell and Charles.
It seemed that Lord Baltimore was troubled by Nell's predicament, and petitioned the Provincial Assembly to change the law to guarantee that no white woman would ever be forced into slavery.
According to the slave laws, the legal status of the children was determined by their mother's status. "A free mother would have free children, and an enslaved mother's children would be slaves," Callum says.
In 1710, Charles and Nell's grandchildren used that law to sue for their freedom.
At about the time of the Revolutionary War, they won.