Challenges to the legality of bondage, shown in acclaimed director Steve McQueen’s film 12 Years a Slave—which won the Best Picture for Drama at the Golden Globes on Sunday night—are not without precedence, as evidenced by a document held in the manuscript collections of the New-York Historical Society: a list of persons to be freed. While the film tells the story of the unlawful enslavement in 1841 of Solomon Northup, a free African American from upstate New York, the N-YHS list is related to an earlier case in Maryland. Northup, played by Chiwetel Ejiofor in the movie, was kidnapped in 1841 on the streets of Washington, D.C., and sold into slavery in Louisiana, where he labored for twelve years on bayou plantations.

His 1853 memoir depicts the horrors of American chattel enslavement from the perspective of a freeborn man who had lived that way for decades. His slave narrative went on to contribute to the national dialogue on abolition. Northup was unsuccessful in his pursuit of legal action against his captors, as the laws of the jurisdiction prohibited his testimony against a white man in the nation’s capital, the scene of the crime.

A half century before, in the courts of the neighboring Upper South state of Maryland, Charles Mahoney successfully challenged the legality of his enslavement. Mahoney brought suit in 1791 against Father John Ashton, an influential Catholic Procurator General, Jesuit missionary, head of the White Marsh Mission, and slave owner. Mahoney received a favorable ruling in Maryland’s Court of Appeals in May of 1799. Mahoney’s counsel had successfully argued that he be manumitted on the grounds that he was a descendant of a freewoman, Ann Joice, who had been unlawfully enslaved. (Joice’s descendants had long asserted their freedom, and in 1770 her grandsons, the brothers Jack Wood and Jack Crane, took an axe to the neck to the man who claimed to be their overseer.)...