Belinda Thomas knew the 200-year-old fireplace stove had to be somewhere behind the plaster walls in the pantry, hidden over the years by many renovations to the mansion at Oatlands Plantation. A few weeks ago, after chipping away the layers, she found it, fully intact. The stove still had the metal hooks upon which a bar holding pots over the fire would have hung.

"It's unusual, because the stove was usually outside the home in those days," said Thomas, director of education at the former wheat plantation south of Leesburg. "This was such an amazing find, especially in our bicentennial year."

The stove was one of many significant discoveries made possible through the grants and monetary gifts that pay the salaries of such employees as Thomas and fund the preservation of Oatlands, a national historic landmark and one of Loudoun County's most popular tourist attractions.

The plantation draws about 60,000 visitors a year. It offers tours through beautifully manicured gardens and restored buildings, special events such as herb fairs and art shows, and a sanctuary outside the rush of Washington's busy city life.

This spring, as Oatlands began celebrating its 200th anniversary, it received news of a surprise gift of at least $1.25 million from the estate of Valeria Harris Symington, a farmer who lived in Loudoun for 70 years before her death in August 2003 at age 87.

"It is indeed the most generous gift since Oatlands' inception as a National Trust [for Historic Preservation] property" in 1965, said David Boyce, Oatlands' executive director. "What makes the Symington gift so utterly unparalleled and amazing is that it's unrestricted."

Boyce said no decision has been made on how the money will be spent after it is disbursed in August. Oatlands will also receive a share of the residual estate when it is settled.

One option, Boyce said, would be to use some of the money to obtain matching grants -- such as the $60,000 Getty foundation grant that Oatlands received five years ago -- for research and historical preservation of the plantation and its many buildings. That grant, which paid for a detailed assessment of the conditions of several buildings, led to additional money from the National Trust's historic sites fund to restore the greenhouse.

The greenhouse, which dates to 1810, is the second-oldest propagation greenhouse in the nation, one in which the plants move on to survive outdoors. Research allowed for historical authenticity when the greenhouse was renovated. The mortar was made from clay on the property, and the wooden floor planks were cut from trees on the grounds that had fallen during a windstorm.

"We painstakingly restored it to the age of George Carter," Boyce said. Carter inherited the plantation from his father and in 1804 began building a mansion, the greenhouse, a dairy, smokehouse, barn and gardens. Carter added to his original home throughout the years and renovated the Federal-style mansion into its current Greek Revival style in the 1820s. Carter also owned as many as 128 slaves, the largest holding in Loudoun, according to the 1860 county census.

After Carter died in 1846, his widow and their two sons remained at Oatlands and managed the property through the Civil War. After the war, beset with debt and the loss of their slave labor, the Carters operated Oatlands as a summer boarding house. They sold the property in 1897 to Stilson Hutchins, a co-founder of The Washington Post. Hutchins, however, did not live at Oatlands, and the mansion sat empty for six years.

Some of the research efforts have gone toward identifying additions made by the Eustis family, which bought the mansion in 1903 and whose daughters donated it and 261 acres to the National Trust in 1965.

"Grants and donations have really opened up the ability to interpret the plantation," Thomas said. "In a place like this, you're always learning."

Oatlands has had difficult times in recent years. Its $5.3 million endowment generates about $70,000 each quarter, leaving a huge gap in its $1.3 million annual budget to be filled with membership and admission sales, special events and grants. Slumps in tourism after the Sept. 11, 2001, terrorist attacks and the 2002 sniper attacks also hurt.

Since then, Oatlands has put more emphasis on events, such as art, herb, antique and wine shows, giving more reasons for locals who have visited the plantation three or four times to come back for more.

The plantation is also holding more weddings and wedding receptions. Wedding coordinator Joe Forcino said the number has jumped about 60 percent to about 25 weddings a year, mostly in the summer.

Use of the grounds for a Saturday wedding costs $4,500.

Oatlands members are even more adamant about preserving the property now that clearing has begun for a housing development just outside the plantation. A 277-home development called Courtland Farms is slated to be constructed in an area adjacent to the 2,500 acres surrounding the plantation, despite a lawsuit filed by the National Trust for Historic Preservation and other nonprofit groups.

"Two hundred years is a long time," Boyce said. "We want to make this property last another 200 years. I want to preserve this property for the coming generations."

Oatlands kicked off its bicentennial party with an auction of rare wine in March. The auction's top bottle, a 1999 Paracombe Sommerville Shiraz, went for $120, while an antique corkscrew from 1804, the year Oatlands' mansion was built, brought in $160.

One of the most anticipated events is the Bicentennial Birthday Bash on July 10. Although plans are still being finalized, organizers say it will be an all-day affair with a variety of activities, music, food and speakers.

The property is open for general tours from April through December, and group-specific tours can be arranged.

"We had a group interested in needlepoint, so I created a tour for that," Thomas said.

She recently developed a "sandbox tour," now part of the regular curriculum, that she said teaches children about the value of archaeology and history. Thomas buries various items, which the children dig up, identify and must imagine their significance hundreds of years ago.

"It's a great area to show children that history isn't just a stagnant place -- it's about discovery of everyone's past," Thomas said.