Well-known Philadelphia philanthropist H.F. "Gerry" Lenfest has donated $4.1 million to buy a historic piece of land for the proposed American Revolution Center.

A center official made the disclosure yesterday after The Inquirer obtained records showing that the sale occurred just hours after Lower Providence Township supervisors approved a controversial zoning amendment last week.

Plans are to build a 130,000-square-foot museum, a 99-room hotel and conference center, a restaurant, and other attractions that ARC officials say are necessary for the museum's financial success. Lenfest is chairman of the center's board.

"It's for a good cause," he said of his donation.

ARC's parent organization, the National Center for the American Revolution, bought the 78 acres within the congressionally authorized boundary of Valley Forge National Historical Park from the Archdiocese of Philadelphia. As part of the deal last Friday, Montgomery County bought an additional 48 acres earmarked for open space for $3 million.

Lenfest, rather than the organization itself, had secured an agreement of sale for the entire parcel in November, according to settlement documents.

The 78-acre tract is part of the 785 acres of Valley Forge parkland in Lower Providence, but Congress has never appropriated money for the National Park Service to buy this piece.

The zoning amendment limits development to 25 percent of the 78 acres, or less than 20 acres. The rest will be preserved as open space, although the ordinance includes walkways, plazas and courtyards as open space.

The ordinance could be amended to allow additional development at a later date, which prompted some local officials to ask that the center agree to a permanent "conservation easement" to keep the open space undeveloped.

It refused.

"We would have liked to see conservation easements, but they said they were not interested," said Steven Nelson, Montgomery County's chief deputy operating officer.

The Lower Providence supervisors adopted the zoning amendment, 3-2, with Supervisor Rick Brown dissenting because it lacked the easement.

"I've dealt with developers enough to know that a handshake just doesn't work," Brown said, but "they wouldn't agree to a covenant."

Said Lenfest: "They had a conservation easement that so restricted the property, I didn't feel it was appropriate. I can't tell what we will need 10, 20 years from now."

Thomas M. Daly, president and chief executive officer of the American Revolution Center, said the museum would be the first in the country to tell the entire story of the American Revolution.

"We've had a long time to develop our vision of a compelling story and unique educational experience for our visitors," Daly said in a statement. "This land purchase takes all of our planning into the realm of reality."

Originally, the museum was to be built in the park next to the Welcome Center as part of a public-private partnership between ARC and the park service, but ARC terminated that partnership in early January, saying the government's guidelines on fund-raising were too restrictive.

Lenfest said ARC had tried to locate the museum on park ground, but "we couldn't even go out and raise money because of the conditions."

Opponents of the overall proposal - many of whom support the museum itself - said the plans for the hotel, conference center and other amenities were inappropriate for land that during the encampment of 1777-78 housed the Continental Army's commissary and was a staging area for the troops' departure from Valley Forge.

"The fields of Valley Forge are sacred in American history, but Lower Providence supervisors voted as though Valley Forge is just another field," said Joy M. Oakes, senior Mid-Atlantic regional director for the National Parks Conservation Association.

ARC's presentations focused on the need for a museum, but that was not the issue, Oakes said. The issue was whether you take land that was redolent of history and intensely develop it, she said.

ARC owns or controls about 12,500 historical artifacts and documents, according to a 2005 survey. The Valley Forge park collection numbers more than 344,000. Curators said a combined collection of Revolutionary War-era materials would have been one of the finest in the world.

The $150 million project still needs permits from several agencies, including the state Department of Transportation, and land approval from the township before construction can begin.

ARC officials gave no date for the start of construction.