Madison was born into slavery at Monticello, where his mother Sally Hemings was a mixed-race enslaved woman inherited by Martha Wayles Skelton, the wife of Thomas Jefferson. (Sally and Martha were reported half sisters, both fathered by the planter John Wayles. Wayles was said to have a "shadow family": six children with Betty Hemings, whom he enslaved after his third wife died.) As the historians Philip D. Morgan and Joshua D. Rothman have written, there were numerous interracial relationships in the Wayles-Hemings-Jefferson families, Albemarle County and Virginia, often with multiple generations repeating the pattern. According to his memoir, Sally Hemings told Madison that his father was Thomas Jefferson, and that their relationship had started in Paris in the late 1780s, where he was serving as a diplomat. Pregnant, she agreed to return with Jefferson to the United States based on his promise to free her children when they came of age.