Thus were two newcomers to America cast into racially predetermined roles. Today, as new genealogical research illustrates, Ketanji Brown Jackson and Patrick Jackson are left with a historical subject in common: enslaved people. His ancestors owned them, while her ancestors were them.

“As more and more families from different backgrounds marry into one another, the experience of their ancestors is going to have a lot more variety than it might have had a hundred years ago,” said Christopher C. Child, senior genealogist with the New England Historic Genealogical Society in Boston. “This is what is happening over time.”

Few know the Jacksons’ ancestry better than Child and his colleagues. Shortly after President Biden nominated Ketanji Brown Jackson to the Supreme Court in February 2022, Sarah J. Dery, NEHGS’s research and library services manager, began to dig into Jackson’s roots. Child already had co-written a book on a line of Patrick Jackson’s relatives, as well as an article about a man enslaved by Patrick Jackson’s distant cousin. Child, Dery and other genealogists have since delved deeper into the subject, sharing their findings with The Washington Post.

The Jacksons met in a history class at Harvard, but the familial paths that took the couple there could not have been more different. Ketanji Brown Jackson, one of the country’s nine most powerful legal arbiters, tracks her family history through generations of enslavement and coercive sharecropping. Patrick Jackson, a gastrointestinal surgeon in D.C., counts among his ancestors King Edward I of England, four Mayflower passengers and a signer of the U.S. Constitution.

“We were an unlikely pair in many respects,” Ketanji Brown Jackson said in a 2017 speech, noting their respective family histories and areas of study, “but somehow we found each other.”

Patrick Jackson’s family history is well documented. In addition to his royal and Pilgrim ancestry, his distant cousins include Herman Melville, 15 U.S. presidents and a half-dozen governors of Massachusetts. His great-great-great-great grandfather Peter Chardon Brooks was the richest man in New England when he died, having made his fortune insuring ships, including some involved in the slave trade.

One thing many of his well-to-do relatives on his paternal side had in common was a Harvard education. All told, the family has at least 30 Harvard graduates over the course of 12 generations, according to Child’s research, including Patrick, who graduated in 1991. One generation of Ketanji Brown Jackson’s family had attended college before she went to Harvard and graduated a year after Patrick.

Patrick was raised outside Boston, but his maternal grandfather’s ancestors lived in the South. Based on public slave schedules from 1850 and 1860, Child estimates the family owned about 189 enslaved people at the time. “Every male ancestor of Patrick’s maternal grandfather over the age of 21 alive in 1850 or 1860 was a slaveowner,” Child said. One of his ancestors was also a Confederate soldier.

So well documented were the lives of some of Jackson’s prominent ancestors that narratives of some of the people they bought and sold can also be found. One of them was a Black man named Silvanus Warro, enslaved by colonial settler and civic leader Daniel Gookin in the 1600s. Gookin brought Warro to Boston from Maryland and promised to set him free but ultimately reneged and rented him to a local deacon. Warro remained enslaved until his death.

Then came a man identified as Chance, born in slavery to one of Patrick’s relatives in Marblehead, Mass., in 1762, according to a 2010 article by Child in American Ancestors magazine. When he turned 14, his enslaver leased “all rights & title to my Negro boy Chance & his Services, for the space of twelve years” to another man for the sum of 30 pounds. That slavery was effectively eliminated in Massachusetts seven years later appeared not to matter: Chance remained enslaved until the lease expired.

Patrick’s ancestor Patrick Tracy, a wealthy merchant who came to Newburyport, Mass., from Ireland, went against the family’s stance on slavery. He freed his enslaved worker Apropos and his wife after “the idea began to spread that even men of dark skins might love the rights of freedom,” according to “A Memoir of Dr. James Jackson,” an ancestor. When he died, Tracy left to “my faithful black man Apropos” a home to live in and six pounds a year, and he instructed his children to join “in assisting him to render his life comfortable,” according to his 1789 will.

Patrick Jackson, meanwhile, positioned himself as an “ally” of people of color at Harvard, a classmate told the New York Times, taking classes in Black history and social justice. In his spare time, he served as a director on the Committee on Help for the Advancement of Needy Children Through Education (CHANCE), which worked to help a diverse group of local high school students attend college. Patrick Jackson and Ketanji Brown Jackson did not respond to interview requests.

Her family welcomed Patrick into their home in Miami, where she grew up; her father, Johnny Brown, was the chief attorney for the county school board and her mother, Ellery Brown, was a school principal. While the Brown family was generally aware of Patrick’s background before the two married, they apparently knew nothing of his ancestors’ long history of enslaving Black people.

“I don’t think it came up at all, nor was it a point of interest or concern,” Calvin Ross, Ketanji Brown Jackson’s uncle and a former Miami Police Department chief, said of Patrick’s family history. “We had two people who loved each other, and that was enough. You can’t rewrite history. It is what it is.”

But many of Ketanji Brown Jackson’s relatives have taken great interest in their own family history. A two-page written version of John Greene’s story, “Our Family,” is widely circulated at the family’s large reunions. Greene, as the story goes, was born free and was warned not to disembark from his ship in Charleston, a hub in the slave trade. But because of “‘the independent mindedness’ (stubbornness) which characterizes the family, John went ashore, was captured and sold as an enslaved person to the Sharp Plantation. There he met Ella who was a slave.” After slavery was abolished, John and Ella moved to Georgia, and he helped his three brothers and sister come to America, according to the family story.

As with much African American history, documentation of the story is not easy to find. Few enslaved people were able or permitted to write their own history, and early documents generally record their existence as property and rarely include their full names.

“You can find the names, the ages, and it all seems to fit together, but it’s very hard to find that golden record that proves it all true,” Dery, the genealogist, said.

Dery, however, was able to identify several enslaved people she believes are the justice’s ancestors and whose information coincides with the family story. While she was unable to trace a John Greene from Trinidad, she found several people she believes were his descendants linked to a plantation in Randolph County, Ga., owned by John P. Sharp: a “domestic servant” (probably a formerly enslaved person) named Peter Green, and Anderson and Callie Green, who lived two houses away, according to the federal census. All three of those names, with a slightly different spelling of their last name, appear as John’s siblings in “Our Family.”

Ten years later, the 1880 federal census recorded a John and Ella Green in Edison, Ga., where three generations of Ketanji Brown Jackson’s family would come to live. Tax records from the same year list freedmen John, Peter and Henry Green, who the genealogists believe were very likely Jackson’s ancestors.

“There’s always some fact that travels along with family lore,” said Lindsay Fulton, NEHGS’s vice president of research and library services, “so the fact that the family knows this story, the family gave us those names, and the names appear in the records we are looking at.”

John Green’s granddaughter Euzera and her husband — Ketanji Brown Jackson’s grandparents — moved the judge’s maternal line from Georgia to Florida in the mid-20th century; she worked as a nurse’s aide and he as a landscaper at the Miami airport. On Euzera’s maternal side, Dery thinks Ketanji Brown Jackson’s great-great-great-grandfather was a man named Henry Merriweather, whom the genealogists believe was enslaved in the mid-1800s by a wealthy plantation owner named Michael Dennis in southwest Georgia.

In November 1865, Dennis wrote a letter to the Freedmen’s Bureau, the government agency established to help recently freed enslaved people, listing the names, ages and physical condition of the people he had formerly enslaved, including a 55-year-old Merriweather, who was described as “unsound.” Dennis also wrote with astonishment that, while he had offered annual work contracts to the more than 100 Black people he had previously enslaved, “this they positively refused to do for any consideration.” He said he hoped the government would help persuade them to sign.

“He was acting as though slavery still existed,” said Willie James Watson Sr., Ketanji Brown Jackson’s distant cousin and Merriweather’s great-great-grandson.

The genealogists also found a well-documented link to slavery on Ketanji Brown Jackson’s paternal side. Her great-great-great-grandfather was Olmstead Rutherford, who after the Civil War lived with his wife and their seven children in Houston County, Ga., on a 700-acre plantation owned by John H. Rutherford, probably their former enslaver.

In January 1867, Rutherford, who enslaved 65 people before the war, signed a sharecropping contract with 11 people who shared his last name, including “Armstead Rutherford + children + wife Lucy.” Apparently unable to write, Armstead, as his name was sometimes spelled, and the other freedmen signed the document with an X. None of them were to be paid for their labor, instead receiving rations and one-fourth of the crops they cultivated.

“It was just another form of slavery,” Dery said.

Olmstead soon registered to vote and signed the Oath of Allegiance to the United States, as was required of citizens in the former Confederacy.

One hundred fifty-five years later, Olmstead’s great-great-great-granddaughter became the first Black woman to serve on the Supreme Court.

Much of what happened in between remains unknown. The genealogists’ group is hopeful that as information about Ketanji Brown Jackson’s ancestors is made public, more relatives will come forward with details of family history. But as some of Ketanji’s family members see it, they already know the most important part of the story, spelled out on those two sheets of paper handed out at family reunions.

“It is from these roots that the family has grown to its present state,” the Greene family narrative concludes. “The family takes great pride in its contribution to the development of America. The roots of this family grew the food, felled the trees, and labored in all of the great undertakings which forged the great nation of the United States of America.”

Sally H. Jacobs is a former reporter for The Boston Globe and the author of the forthcoming “Althea, The Life of Tennis Champion Althea Gibson.”