That event, on July 9, 1776, has been cleaned up in memory. Nineteenth-century images of it depict festive crowds (including women in hoop skirts), but in reality it was “a bunch of soldiers and sailors,” Mr. Stephenson said, led by an artillery officer, Capt. Oliver Brown, who was so embarrassed it took him decades to admit it.

“We tend to think there was a script we were all speaking from, but the reality was messy,” Mr. Stephenson said. “I guess we might be considered a little bit critical of originalism in that sense.”

The museum, which grew out of the collection of the Valley Forge Historical Society, displays about 500 objects, from the expected muskets, military uniforms and teapots to more touchingly human ones, like a pair of baby shoes made from a British redcoat that a soldier in the Continental Army brought home after the war — beating swords into footwear, if you will.

The immersive exhibits infuse 18th-century history with distinctly 21st-century theatrical shock and awe. There are seven tableaus featuring uncannily realistic life-cast figures, like “A Brawl in Harvard Yard,” which shows George Washington breaking up a fight between troops from New England and Virginia in the early days of the war, an incident later documented in a pension application. (All scenes are based on real people or events.)