The mansion Riversdale was built in the early 19th century by a family that fled Antwerp to escape Napoleon's troops. It brought its collection of Old Master paintings with it, displaying them in 1816. (John Kelly/The Washington Post)

Here’s my pitch. I see this film as a heist picture. It’s “The Thomas Crown Affair” meets “Ocean’s 11.”

In breeches.

The year is 1816, and a gang of dapper, wise-cracking art thieves is planning to steal the greatest collection of paintings ever assembled in the Western Hemisphere. An amazing array of Old Masters — by the likes of Peter Paul Rubens, Anthony van Dyck, Jan Brueghel and Rembrandt van Rijn — is just waiting to be plucked.

And where are these works? On a plantation in Prince George’s County, Md.

Who’d a thunk it?

"It's totally incongruous," said Arthur Wheelock, curator of northern baroque paintings at the National Gallery of Art. How did such famous works come to find themselves just outside Bladensburg, Md., far from the courts and ateliers of Europe?

The story is being told at Riversdale, the historic house owned by the Maryland National Capital Park and Planning Commission.

The mansion was built between 1801 and 1807 by Henri Joseph Stier, a wealthy Flemish financier who had spirited his family out of Antwerp as Napoleon started to carve up the Continent. Stier was concerned not just about his family's safety, but with the art collection his wife's father had assembled.

“These were exactly the type of paintings that were being grabbed by the French,” Arthur said. “Stier was absolutely right to try to prevent that and get them in safe territory. That’s his whole reason for coming to America.”

Stier and his family — and 63 valuable paintings — came to the United States in 1794. They first settled in Philadelphia, before moving to Maryland and building Riversdale. (It was Victorian developers who removed the “s” when creating the town we now know as Riverdale.)

Stier and his wife, Marie Louise Peeters, returned to Europe in 1803, leaving their adult daughter Rosalie. She had married George Calvert, a descendant of the fifth Lord Baltimore.

Some of the precious paintings were hung at Riversdale, but most remained safely in their packing crates, inspected regularly by Rosalie. In one letter to her father, she wrote, “Last year we opened one case, it smelled like paint. I wiped the surface with a silk handkerchief, thus removing white spots that looked like mold.”

Though historians were vaguely aware of the collection, details were scarce. Then, in the mid-1980s, historian Susan Pearl started working on a history of Riversdale for the Maryland National Capital Park and Planning Commission. She found a genealogist in Brussels who had access to a treasure trove of information about the Stier-Peeters family. He sent her boxes and boxes of document copies. Among them were packing slips for the paintings.

Susan realized that she had the means to track the paintings. What did they depict? Had anyone seen them while they were in America? Where had they ended up?

She contacted Arthur, the National Gallery’s Old Master master.

“I thought he was going to hang up on me,” Susan said. “Instead, he said, ‘Bring these papers and meet me at the gallery for lunch at your earliest convenience.’ ”

With his help, Susan started tracking the paintings. She’s been doing it for 20 years.

There were portraits by Van Dyck. There was a delightful scene of animals entering Noah’s Ark, painted by Brueghel and now in the Getty in Los Angeles. There was “Cimon and Pero (Roman Charity),” painted around 1630 by Rubens and now in Amsterdam’s Rijksmuseum. (It might startle today’s viewers, depicting as it does a woman secretly breastfeeding her father, who has been sentenced to death.)

Said Arthur: “These are the kind of names that the artists in America would go to Europe to study.”

Now they could go to Riversdale, and some did, including Gilbert Stuart and Rembrandt Peale. It was Peale who helped persuade Rosalie to open her house to visitors before she sent the paintings back to her father after Europe had settled down.

And now Riversdale has been hung with reproductions of 16 of the paintings.

“They were bowled over,” Susan said of visitors to what in April 1816 was the young country’s greatest art museum. “I’m sure it was buzzing.”

Said Arthur: “I can just imagine the word-of-mouth rippling between Washington and Philadelphia. I can just envision how it builds: a little slowly, then people hear about it and a few more carriages go.”

Does one carriage contain thieves holding a forged letter of introduction, a powerful sleeping draught and special tools to razor the priceless canvases from their frames?

In my movie it does.

"Some of the Finest Paintings Ever in America" is the name of the exhibit, and it runs through Oct. 23 at Riversdale, 4811 Riverdale Rd., Riverdale Park. Walk-in tours are offered Friday and Sunday between noon and 3:30 p.m. or on other days by calling the Riversdale Visitor Center: 301-864-0420. Admission is $5, $4 for seniors, $2 for students. For more information, visit history.pgparks.com and click on "calendar of events."

Twitter: @johnkelly

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