After feuding bitterly for 10 months, the heirs of Marion du Pont Scott today agreed to abide by Scott's will and turn her large Virginia estate, 95 miles southwest of Washington, into a museum honoring the country's fourth president.

Scott's nephew, Henry du Pont, who filed suit in January over the will, agreed to give up his dream of living at Montpelier and sell for $2 million his one-fifth interest in the one-time home of James and Dolley Madison to a historical society, as Scott wanted.

In return, Henry du Pont's siblings agreed to allow their brother's heirs to receive their share of $3.1 million in income from Scott's trust fund. The siblings had contended that Henry du Pont had forfeited the money by not selling his interest by August.

The National Trust for Historic Preservation, which will acquire title to Montpelier, hopes to open the mansion to the public on selected days this year, and to allow regular tours within two years, said Catharine Gilliam, assistant general counsel for the Washington-based organization.

The dispute over the 2,677-acre estate had divided members of one of American's wealthiest families.

Scott was the great-granddaughter of E. I. du Pont, founder of the giant chemical and plastics manufacturer, and the daughter of William du Pont, a banker who bought the estate in 1900.

Scott, a Virginia horse breeder who was briefly married to cowboy movie star Randolph Scott, inherited Montpelier from her father. She died last fall at the age of 89.

Today's settlement, dubbed "the global agreement" because of the multitude of issues it covers, took all the effort of "the North Atlantic Alliance," said J. Thomas Province, one of the lawyers involved in the suit.

More than two dozen attorneys labored over it, often flying to conferences in private planes, representing every possible du Pont family interest, including the concerns of the unborn progeny of children who might one day be adopted.

In the process, they ran up legal fees estimated to be $1 million or more.

Meetings over the will in the Albemarle County Courthouse here often resembled bar conventions.

Attorneys and family members appropriated the courtroom, the jury room, judges' chambers, outdoor benches and law offices across the street for as long as eight hours at a stretch.

No sooner would one issue be settled than a new, seemingly more stubborn one, cropped up.

On Oct. 3, negotiations "broke down completely," said Leonard Togman, an attorney for two family members, when Henry du Pont insisted the estate's executors and trustees were not entitled to pay their attorneys out of the estate -- a point on which he later relented.

The talks nearly collapsed again four days ago over how many rooms at Montpelier should be dedicated to Scott's father, and which ones.

Morris Weisberg, an attorney for Henry du Pont, and his brother John, argued "It's going to be the morning room and drawing room or nothing." The National Trust, which had received $10 million from Scott to turn the estate into a museum for Madison, wanted to dedicate only one room, Weisberg said. Today's agreement calls for dedicating both rooms to him.

For the first months of the suit, a settlement seemed as unlikely as the chance that Montpelier's peach-colored mansion, set in the rolling hills of nearby Orange County, would turn into a woodshed. "There was a time . . . it seemed impossible to resolve," Albemarle Circuit Court Judge E. Gerald Tremblay said today.

Henry du Pont was determined to live on the estate, and contended Scott violated her father's will by trying to turn it over to the public. Scott declared in her will that unless her five nieces and nephews gave or sold their interests in Montpelier to the National Trust, their children could not benefit from her trust fund -- a proviso du Pont saw as nothing less than blackmail.

He and another brother, John, sued the National Trust, the estate's executors and the trustees to have that provision of the will thrown out.

His sisters and a half-brother intervened as defendants, along with their children and grandchildren.

Feelings were very "heated," in Tremblay's words, when the parties got together in his court last spring. Attorney Weisberg described his clients' sister, Jean, in court as "implacably hostile." Attorneys for the defendants described Henry as incurably "litigious," citing another family lawsuit he initiated over his father's will some years ago.

Henry du Pont's wife, Muffin, said her husband finally decided to sell his share in Montpelier to the National Trust partly because his children were being told their cousins "were going to get their money" from Scott's trust fund if he didn't.

Du Pont and his brother John agreed to sell for $2 million each -- about $700,000 more than their three siblings received from the National Trust for their interests.

Since he agreed to abide by Scott's will in the end, some attorneys said they wondered what the purpose of du Pont's suit was. "It was pointless, the whole thing," said Togman, who represents Henry's sister Evelyn and half-brother William. "How would you like to have paid a fortune just to get to the same place?"

Weisberg said that while Henry and John du Pont gave up the main objective, they won on several smaller issues involving the estate.

Neither Henry nor John du Pont have signed the settlement agreement, but their lawyers told the judge today their clients would do so within a few days.

Tremblay expressed hope that the 43-page agreement, with 85 pages of attachments, "will bring the family closer together."

But one du Pont heir, who asked not to be identified, said "the family is embarrassed that Henry and John acted to delay the museum and the charitable bequests of Marion Scott."

And Weisberg warned that "another donnybrook" is in store over the issue of attorneys fees. "I don't have any hopes for family harmony," he said. "Maybe the next generation."