Whistler's mother Anna McNeill contested her African aunt's inheritance from her plantation-owning husband, Zephaniah Kingsley Jnr. in Florida.
"Kingsley left much of his land to his wives and children, in a bequest which was immediately contested on racial grounds by his white relatives. Kingsley's niece, Anna McNeill (who married George Whistler; their son James McNeill Whistler became a noted artist) was among the family members who tried to have all of Kingsley's family of African descent excluded from his will."
Kingsley's wife (the others were not treated as actual wives)Anta Madjiguene Ndiayewas only 13 years old when she was captured in what is now Senegal as a high ranking member of the Wolof people. Kingsley purchased her in Cuba and (claimed to have) married her in an African ceremony. Calling her Anna, he freed her at age 18, and relied on her to run his household and probably oversee his slaves, freed slaves and estate when he traveled. After his death in 1843, she was successful in the inheritance lawsuit. Her descendants went on to be wealthy and successful Floridians. The plantation is now owned by the Florida Parks Department.
This Kingsley's father, Zephaniah Kingsley Snr., was Whistler's major slave-trading and owning great-grandfather. It seems possible that Whistler moved to Europe because he didn't (wish to) benefit directly from his grandfather's fortune. However his mother's status was clearly dependent.