He stumbled upon the property accidentally. One afternoon in 2007, while Eric Hadar was driving around looking for the home of a friend in the estate-laden terrain of Bedford, New York, he pulled up to an elderly fellow on a tractor to ask for directions. He realized almost immediately that the man's 45-acre farm, which included an expansive main residence and a large carriage house, was a remarkable piece of intact history.

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The custom beds in a guest room are dressed with spreads from Chelsea Textiles, the chair is from Avantgarden, and the late-17th-century table is French; the curtains are of a Les Indiennes cotton, and the rug is a vintage Indian dhurrie.

On the spot, Hadar, a Manhattan real estate executive who once owned the Citicorp Center, made a handshake deal with the owner, a Quaker whose ancestors had built the place in 1870, but whose grown children had no interest in running it.

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The dining room table is Swedish, and the vintage Liberty chairs are upholstered in assorted Liberty printed cottons.

"I had $60 in my pocket, and I gave it to him as a deposit," says Hadar, who is divorced and has two teenage children. "It was insane. I had no idea how much I might be overpaying—there was no inspection or anything—but I knew it was perfect. And he could see it was my intention to restore the place, which was important to him."

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The carriage house as seen from the garden; the landscape design is by Miranda Brooks.

In the years since, Hadar has slowly begun to revamp the spread, which includes eight outbuildings, some of which still housed inventions the family had bought when they were newfangled: a Ford Model T, a Thomas Edison–era phonograph, an early washing machine, and an electronic telescope. (Hadar is fixing up one of the buildings as a museum-like space, for school groups to visit.) There were also boxes and boxes of photographs from the family's grand tours of Europe and the Middle East in the early 20th century. "It was this time capsule, unspoiled," Hadar says.

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The bathroom sink and fittings are by Urban Archaeology, and the stool was found at a flea market.

He has yet to tackle a full-scale renovation of the main house. But he needed somewhere decent for his kids and their friends to stay in the meantime, so he decided to remake the carriage house into guest quarters. It was in serious disrepair, having long outgrown its original use as a place to keep horses; in later generations, it was used as a sheep barn. He retained as much of the rough stone structure as possible, replacing some ceilings, the mechanicals, and the plumbing.

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The kitchen island is made of a vintage marble slab on a steel base, the stove is by BlueStar, and the shelves are of reclaimed wood found on the farm; the pendant lights are from Rewire, and the floor is concrete.

When it came to the interiors, he didn't want the decorating to be too staid or obvious. So he hired Virginia Tupker, a longtime editor at Vogue, who had recently opened her own interior design practice; she made a splash in 2012 with her first project, the interiors of the Annabelle Selldorf–designed Chelsea townhouse of model-turned–shoe designer Tabitha Simmons and her husband, fashion photographer Craig McDean.

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The newly painted breakfront in the entry belonged to Hadar's mother; it is topped with Spanish terra-cotta pots from the 1930s.

The results displayed the designer's talent for finding creative solutions and burnishing her clients' taste with her own refined aesthetic. "The important thing is to have real instincts about people, and to listen to them," Tupker says. "Well, not just to listen, but to really hear."

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In the living room, the custom sofa is covered in a Kravet cotton, the cocktail table is by Martin Szekely, and the dhurrie is 19th century; the Egyptian light fixture is from Liza Sherman.

With the Hadar carriage house, Tupker's idea was to keep the place cozily rustic, yet not veer into kitschy country territory. To make a new staircase seem as though it had always been there, the designer used reclaimed pine and white oak and sourced the wood in exactly the lengths needed so there wouldn't be freshly cut sides. She had a railing fashioned out of old pipes. And although she poured concrete on top of the original stone floors, she mottled the coloring of the mix, so the floor would have light and dark patches, kept the surface matte, and ground down the concrete in some places to allow the old stone to peek through.

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The headboard in the master bedroom is covered in a 19th-century Pakistani textile, and the spread was made in Venice.

Because she loves color, she searched out plenty of patterned textiles, especially from India, which contrast with the rough-hewn wood throughout. For the headboard in the master bedroom, she used a 19th-century Hindu Bagh from Pakistan, upholstering it in such a way that the textile could later be removed without being damaged and endangering its value. To keep the look fresh, Tupker mixed fine midcentury furniture, including a cocktail table by Roger Capron, lounge chairs by Pierre Jeanneret, and a pendant lamp by Paavo Tynell, with pieces by contemporary designers.

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In the captain's bedroom, a custom mattress by Charles H. Beckley is covered in a C&C Milano linen, the light fixture is by Circa Lighting, and the vintage dhurrie is from Mark Shillen Gallery.

In keeping with Hadar's pledge to honor the intention of the original owners, there are nods everywhere to the family that loved the homestead for so many generations. An antique nightstand found in the basement of the main house now proudly serves in the master bedroom, and Tupker framed a series of sepia photos of mummies, taken decades ago on a family trip to Egypt, that were found among the piles. "The pictures are kind of creepy," she says, "but also fantastic. Eric's kids love them."

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In the sitting area of Eric Hadar's carriage house in Bedford, New York, which was decorated by Virginia Tupker, a soft from Matter holds cushions from Les Indiennes and Nathan Turner, the chairs are by Pierre Jeanneret, and the cocktail table by Roger Capron is from Maison Gerard; the pendant light is by Roost, the ladder is from John Derian, the garden tables are French, and the wool rug is a custom design.

As for the farmer who sold Hadar the place, his presence is even more tangible. Now in his 90s, he's downsized to a town nearby. But he often swings by, unannounced, and sometimes plays tennis on the court he built decades ago. He is always welcome. "We love that he's comfortable here," says Hadar. "He's family."

Megan Tatem

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