Katharine Hepburn, Cary Grant, and Jimmy Stewart made cinematic history for their roles in the 1940 comedy of errors The Philadelphia Story. Yet if a house could win best supporting actor, it should have gone to the Main Line home that inspired the film (and the long-running Broadway play that preceded it). It spoke a thousand words, likely in a mid-Atlantic accent.

Now a portion of the estate, originally owned by the Montgomery family, is listed for sale at $13.4 million. That parcel is an L-shaped residence converted from the original 50-horse stable that was built in 1920. It has a pool, tennis court, “party barn,” gazebo, and the original clock tower, according to Lisa Yakulis, of Sotheby’s International Realty, Bryn Mawr. Twin guesthouses are surrounded by pastures and gardens. Its entrance is private.

The original mansion, Ardrossan (named for the Scottish town where the Montgomerys originated), was completed in 1913. The property then included nearly 800 acres for riding, socializing, dairy farming, and foxhunting, but over the years it was sold off piecemeal, and McMansions now occupy many of its lots.

Its cinematic scale is best appreciated from a helicopter.

The story of Ardrossan—and The Philadelphia Story—began in the early 20th century, when Colonel Robert L. Montgomery, a prominent Philadelphia financier and foxhunter, was chasing tails on the grounds and was thrown from his horse and knocked unconscious. When he came to, he shouted, “Arcadia!” (Pan’s forested Eden).

Montgomery bought the property and recruited Gilded Age architect Horace Trumbauer to render his vision of a Georgian Revival country home, including multitudinous outbuildings. (It’s the kind of configuration only a photographer in a helicopter can capture.)

A dramatic sitting room.

Philip Barry, the writer of the Philadelphia Story play, was introduced to the Montgomery family after he attended a writing class at Harvard with Edgar Scott, who would go on to marry the colonel’s daughter, Hope Montgomery. Barry became a regular at the compound, out-drinking an already cups-friendly family. He was soon intrigued by Hope, and imagined that she could be an interesting character. She first saddled up at age four and, later in life, would ride her ponies to the Devon Horse Show, an hour’s trot on Lancaster Avenue. She personally handled her family’s herd of prizewinning Ayrshire cows, naming all 310 of them. (She had a brood of beagles too.)

It’s the kind of configuration only a photographer in a helicopter can capture.

When she came out as an 18-year-old debutante, in 1922, she was asked for her hand in marriage four times that night, according to The Philadelphia Inquirer. None got it. Instead, a year later she married Scott, an heir to a Pennsylvania railroad fortune. When the colonel died, in 1949, Hope Montgomery Scott began to spend more time at Ardrossan, eventually living there full-time and modernizing its dairy operations.

Not a bad place for a Zoom call: the clock tower has been renovated into an office space.

The Montgomerys invited Barry to fictionalize their so-called Philadelphia Story. In the play, Katharine Hepburn channeled Montgomery Scott as “Tracy Lord,” a socialite and equestrian rethinking a second marriage on the night before her wedding. Her trust-funded, boat-designing ex (played by Cary Grant) shows up uninvited. So does a cynical reporter (Jimmy Stewart), who also falls for her while covering the nuptials for an upscale tabloid magazine called Spy. High jinks ensue.

Hepburn and Montgomery Scott shared many attributes. Both were slim and athletically built. Both were socialites and tomboys, witty and candid, with the ability to sniff at (and sniff out) aspirant phonies and well-heeled philanthropists alike. Both had cheekbones that could cut Pennsylvania fieldstone.

Hope Montgomery Scott, who was immortalized as Tracy Lord in The Philadelphia Story, at the National Horse Show held in Madison Square Garden in 1929.

Following the success of the play, Hepburn’s friend Howard Hughes backed the actress to buy the film rights. She sold The Philadelphia Story to Metro-Goldwyn-Mayer, and the studio commissioned George Cukor to direct. Cukor decided the “scale” of the 50-room Ardrossan would be inaccessible to mass audiences. The reasoning: “Who lives like that?”

According to David Nelson Wren, author of the photo-history tome Ardrossan: The Last Great Estate on the Philadelphia Main Line (2017), “nothing” in the film was shot on location. The main house was deemed too grand even to fake it, and so, he wrote, “a residence in [nearby] Merion Station was used as a model.”

The film was made on a Culver City lot in six weeks. As for the swimming pool where Grant’s “Dex” memorably sets afloat a replica of the True Love sailboat he and “Tracy” cherished? That was found on Stage 30 in MGM Studios—it was used in many Esther Williams films.

Montgomery Scott died in 1995 at age 90; she was leading two of her donkeys into the stables at Ardrossan when she fell and injured her head. But the philanthropist retained her pizzazz (and social calendar) until the end. According to her Philadelphia Inquirer obituary, her granddaughter, the Pulitzer Prize–winning reporter and author Janny Scott, recalled seeing her grandmother “wearing shorts and a bathing-suit top, riding a tractor through the family’s cornfields.”

Steve Garbarino, the former editor at BlackBook magazine, began his career as a staff writer at The Times-Picayune. Once again New Orleans–based, he now contributes to The Wall Street Journal and New York and is the author of A Fitzgerald Companion