By conventional measures, the man who dreamed up Beauport, the Sleeper-McCann House, is an enigma. Unlike his dear friend Isabella Stewart Gardner, the public-spirited arts patron who founded her own world-class museum, Henry Davis Sleeper kept a low profile, preferring to spend time with family and intimates at his town house in Boston and at Beauport, his summer home in Gloucester, Massachusetts. An antiquarian and collector who would eventually become one of America’s first professional interior decorators, he never partnered or had children, and after his untimely death from cancer in 1934, at age 56, nearly all of his personal and business papers vanished.

That year, Helena Woolworth McCann, daughter of the famed Five-and-Dime entrepreneur Frank Winfield Wool- worth, bought Beauport and its contents, and had the good sense to leave it all largely intact. In 1942, her daughters donated the estate to Historic New England, the oldest historic preservation organization in the United States, ensuring that Sleeper’s unique legacy would reach future generations. Here in the 21st century, as upwards of 7,000 visitors learn each year, Beauport isn’t merely a marvelously preserved historic house museum, but also a self-portrait rendered in furniture and decorative items that’s as revealing as any cache of letters or diaries.

Sleeper was 29 in 1907, when he bought a spot of land on a rock ledge overlooking Gloucester Harbor and began designing his dream house. He never stopped. What began as a 22-room Arts & Crafts stone-and-shingle summer retreat for himself and his mother, each room designed around a historic figure or theme, grew into a nearly 10,000-square-foot mansion, more than 40 rooms strong, each distinguished by a color, shape or object. The facade bristled with turrets and gables, even a dovecote and belfry.

Very quickly, Beauport became equal parts private quarters, entertaining space and—once Sleeper’s guests got a look at his talents—designer showcase for his burgeoning career as an interior decorator. Among his clients were Henry Francis du Pont (who hired Sleeper to help with his summer home, as well as Winterthur), a Vanderbilt, several Hollywood actors and a chain of beauty salons. But Sleeper’s most precious project was the eternally evolving Beauport, which he added to with the same frequency that he built his beloved collections of antiques and objects.

“I’m planning to make a new room at Gloucester….Of course I have all the details visualized and am enjoying it accordingly,” Sleeper wrote to Gardner in 1921, on his way home from France. While there, he’d done what he always did: fall headlong for an everyday decorative element and amass as much of it as possible. In this case, it was antique toleware, tin that’s painted red to imitate Japanese lacquer. He’d call this latest addition the Octagon Room, he explained; everything from the room’s shape to the doorknobs would be eight-sided, and the walls painted black, to better display his finds.

Sleeper had an exceptional eye for color and detail, absolutely. But that wasn’t the extent of his talents: His vast and varied collections of Americana—assembled at a time when most Gilded Age elites filled their homes with European antiques—spoke to a quiet but firm unconventionality. “While Isabella Stewart Gardner was collecting Old Masters, and Edith Wharton and Ogden Codman Jr. were establishing guidelines that told readers exactly what to do, Sleeper was playing by his own rules,” said Martha Van Koevering, the current site manager of Beauport. “He embraced and elevated everyday objects to create striking decorative displays, whether he was using salvaged window shutters as paneling or arranging 130 pieces of ordinary colored glass into a three-dimensional window.”

His use of ample salvaged materials—paneling, doors, windows—shows a great respect for the past, and an innate understanding that restoration can also be an act of imaginative creation. Whimsical flourishes—a wood stove in the shape of George Washington; stone-carved ghouls, goblins, and mermaids adorning the facade—show a man with a sense of humor, who prioritized human engagement over producing a grand effect.

Beauport was repeatedly featured in the era’s national magazines, from Vogue and House Beautiful to Architect and Country House, as were Sleeper’s collections and many of his commissioned projects. But even the most expert photographs can’t entirely capture how it feels to be inside such a place: The most surprising feature of this wildly inventive house remains how, in spite of its size, and its breathtaking views of the harbor and beyond, it feels so cozy within. A walk through it creates the sensation of a rambling, intimate conversation with a wonderfully curious and considerate interlocutor, one who takes care to both edify and amuse. Maybe someday Sleeper’s lost papers will turn up, and we’ll learn more about him. Until then, Beauport itself serves as an enchanting biography.

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This story originally appeared in the Spring 2022 issue of FREDERIC. Click here to subscribe!