A party with a historic theme -- Gen. George Washington's wedding to Martha Custis -- will be held Saturday, featuring food similar to what was served that December day in 1759 and entertainment and dance instruction by the English Country Dancers.

The wedding-themed festivity is to commemorate the 100th anniversary of the founding of the Westmoreland County Historical Society. The party will be held from 6 to 9 p.m. in the Westmoreland County Courthouse in Greensburg.

Robert Hanna's Dark Horse Beer, brewed by the local Red Star Brewery to commemorate the founder of Hanna's Town, will make its debut at the event.

The 250th anniversary of the Washington wedding and the society's centennial reflect the long and rich history of the area, said Lisa Hays, the society's executive director.

"Most people associate Westmoreland County with its history as a coal and coke mining region," she said. "But this was the proving ground for the young Washington, and a central front during the Revolutionary War."

Founded in 1908, the nonprofit Westmoreland County Historical Society has a 700,000-item archival collection and the 5,000-volume Calvin E. Pollins Memorial Library for local history and genealogical research. All are in the Stark Building in downtown Greensburg. The society has a staff of six and is run by a 15-member board.

With Westmoreland County Parks and Recreation, it maintains Historic Hanna's Town in Hempfield, a partial reconstruction of the first county seat of Westmoreland, which was founded in 1775. Much of Hanna's Town was burned to the ground in 1782 by American Indians allied with the British in one of the final battles of the Revolutionary War.

The destruction of Hanna's Town and the 1786 decision to move the county seat to its present home in Greensburg resulted in one of the historical society's greatest treasures -- the archaeological collection excavated from the site, which numbers more than a million pieces, Ms. Hays said.

"After everyone left, the area became farmland, leaving everything below a couple of feet undisturbed," Ms. Hays said. "It's a unique snapshot of how people in Westmoreland County were living in the late 1700s."

The tools and pieces of pottery from the collection, some imported from overseas, show the important role that Westmoreland County played in the settling of land west of the Allegheny Mountains, she said.

The collection is housed at Westmoreland County Community College. The Hanna's Town site has been only partially excavated, Ms. Hays said, and the society has big plans for its future.

In 2007, the society began a capital campaign to raise $7.5 million for further excavation and for a history education center on the Hanna's Town site. The county has pledged $1.1 million and the groundbreaking had been planned for this spring.

But, as board chairman and Greensburg attorney P. Louis DeRose noted, the economic climate has forced the society to revise its plans.

"Corporations and other organizations have cut their giving to nonprofits like us," he said. Volunteers are the lifeblood of the society, he added.

Along with administering Hanna's Town and maintaining its archives, the society offers educational programs to schools and the public, publishes Westmoreland History Magazine and a quarterly newsletter, and coordinates the efforts of the smaller historical societies in the area.

Ms. Hays said that although times are hard, she believes preserving history remains important to people.

"There are people here all the time researching their family's history in our genealogy library," she said. "People need food and health care, but they need history, too."

She quoted David McCullough, author of a noted biography of John Adams, on history's importance.

"He said history inspires courage and tolerance, and that it is 'an aid to navigation in perilous times,' " Ms. Hays said. "I couldn't say it any better than that."