NEW YORK, NY.- Daniel P. Jordan, who as president of the foundation that owns Monticello, Thomas Jefferson’s plantation in Virginia, broadened its educational mission — and, perhaps most significant, commissioned a study that found that Jefferson had almost certainly fathered six children with Sally Hemings, one of hundreds of people he enslaved — died March 21 in Charlottesville, Virginia. He was 85.

His daughter Katherine Jordan said the cause was a heart attack.

Questions about Jefferson’s relationship with Hemings had circulated among historians, and her family, for two centuries. In 1993, when Jordan invited some of her descendants to a Jefferson commemorative event at Monticello, he was noncommittal on the paternity issue.

“If there’s anything like a party line, it’s simply this,” he told The Washington Post. “We cannot prove it, we can’t disprove it.”

But five years later, his position had to evolve. The results of DNA testing, published in the Nov. 5, 1988, issue of Nature magazine, appeared to confirm that Jefferson was the father of Eston Hemings, one of Sally Hemings’ sons. The tests strongly indicated that Eston had the same Y chromosome mutations seen in the Jefferson lineage.

At a news conference, Jordan said the tests would be evaluated by a research committee at Monticello, which is owned by the Thomas Jefferson Foundation.

“We will follow the truth where it leads,” he said.

A few days later, he told The New York Times, “My immediate reaction was to be reminded of just how vicious, abominable and complex the institution of slavery was.”

In early 2000, the Monticello study validated the DNA findings. But the study went further with its analysis, examining historical and scientific documents and conducting interviews with descendants of people who had been enslaved at Monticello.

“Although paternity cannot be established with absolute certainty,” Jordan said at a news conference, “our evaluation of the best evidence available suggests the strong likelihood that Thomas Jefferson and Sally Hemings had a relationship over time that led to the birth of one and, perhaps, all of the known children of Sally Hemings.”

He added, “Whether it was love or lust, rape or romance, no one knows, and it’s unlikely that anyone will ever know.”

Annette Gordon-Reed, the author of “Thomas Jefferson and Sally Hemings: An American Controversy” (1997) — which examined inconsistencies in scholars’ assessments of the existing evidence of their sexual relationship — said Jordan ably handled the response to her book, and to the DNA results.

“Commissioning the Jefferson foundation study on the matter and accepting the findings were the right responses,” she wrote in an email. “He could have punted.”

Daniel Porter Jordan Jr. was born July 22, 1938, in Philadelphia, Mississippi. His father was a dentist, and his mother, Mildred (Dobbs) Jordan, managed the house. At the University of Mississippi, where he played both baseball and basketball, Jordan studied history and English and graduated with a bachelor’s degree in 1960.

He met Lewellyn Schmelzer, known as Lou, at the university. They married in 1961.

After receiving his master’s degree in history from the university in 1962, Jordan served as an Army infantryman in South Korea and Western Europe and taught history to enlisted men on Army bases through a division of the University of Maryland.

Back home, he resumed his education at the University of Virginia, which Jefferson founded. He received a fellowship from the Jefferson foundation for his studies, and Merrill Peterson, a Jefferson scholar, was his doctoral adviser. He received a doctorate in history in 1970.

Over the next 14 years, he taught history at the University of Richmond and at Virginia Commonwealth University, also in Richmond, where he became chair of the history department. In 1983 he published a book, “Political Leadership in Jefferson’s Virginia.”

When he was named the foundation’s executive director in early 1985, Jordan said his goal was to expand its educational mission. He was elevated to president nine years later.

“We’re in the business of telling people about Thomas Jefferson, of educating them in the best sense,” he told The Daily Progress of Charlottesville in 1994. “It’s great if they know Jefferson was author of the Declaration of Independence, but those facts are secondary to his values and ideas.”

During Jordan’s 23 years at Monticello, publication of Jefferson’s post-presidency letters and other papers began; the Jefferson Library opened near Monticello, on the campus of the Robert H. Smith International Center for Jefferson Studies; descendants of Monticello’s enslaved people began being interviewed for an oral history project called Getting Word; and the Center for Historic Plants was established to collect and sell plants and seeds grown at Monticello, in addition to other historic and heirloom seeds.

“He was interested in the restoration of the gardens,” Peter Hatch, the former director of gardens and grounds at Monticello, who started the plant center, said by phone. “He wasn’t a keen fan of horticulture, but he understood the importance of landscaping when you talked about Jefferson.”

In addition, the plantation’s property was augmented with the acquisition of nearby Montalto mountain for $15 million; the main house’s leaky roof was rebuilt; and the estate’s vineyard was restored.

In 2001, archaeologists identified a slave burial ground about 2,000 feet from Monticello itself.

“It has been a long-standing goal here at Monticello to determine where slaves were buried, and we believe we have now found one such location,” Jordan told The Associated Press. “We regard this as a significant archaeological find, one that allows us to fill in one more piece of the puzzle in our efforts to research and understand all aspects of the Monticello plantation.”

Before Jordan arrived, “it was a mom-and-pop place,” said Susan Stein, the Richard Gilder senior curator of special projects at Monticello. “There were serious scholars here, but Dan elevated them, and me, and he really reimagined the place. He envisioned it as a university. That made all the difference.”

After he retired in 2008, Jordan worked as a consultant for clients including people who managed historic homes like Monticello and other nonprofit organizations.

In addition to daughter Katherine, Jordan is survived by his wife; another daughter, Grace Jordan; a son, Daniel III; six grandchildren; and a brother, Joseph.

Jordan and his family didn’t stray far from Jefferson’s plantation during his years at the helm of Monticello. He and his family lived in a modern house down the hill from the main house. Jordan rose early every Jan. 1 to greet the year’s first visitors. And both Grace and Katherine Jordan were married on its grounds.

“We love being here,” Jordan told C-SPAN in 1997. “Let me point out that we’re not in the main house, and I should say that Thomas Jefferson’s bedroom is not for rent. We live about 150 yards from the mountaintop. It’s just absolutely magical.”

This article originally appeared in The New York Times.