The blue box had a hint of green, almost recalling Tiffany Blue, a color introduced by the jeweler in 1845. Yet this inconspicuous box was circa 1880s, rectangular with smooth, rounded corners, covered with velvet, and lined with blue silk.

Laura Cinturati, a national-park ranger outfitted in her government-issued gray-and-greens, took a breath as we opened the front metal clasp. Inside was a silk-covered divider with two blue ribbons. What we found as we lifted the divider altered much of what we know about Theodore Roosevelt and his first, lost wife, Alice Hathaway Lee.

Alice was beguiling and beautiful, one of Boston’s most eligible Brahmin bachelorettes. She was the daughter of George Cabot Lee and hailed from a family so celebrated in that golden age that they were the centerpiece of a popular piece of doggerel, “The Boston Toast”:

And this is good old Boston,
The home of the bean and the cod,
Where the Lowells talk only to the Cabots,
And the Cabots talk only to God.

Hathaway Lee, one of Boston’s most eligible Brahmin bachelorettes.

Roosevelt, of course, was a Knickerbocker, a term popularized in Washington Irving’s satirical A History of New York (1809) to identify the descendants of Dutch settlers in colonial Amsterdam. The Brahmin is of ancient Sanskrit origin, the name of India’s highest priestly Hindu caste. It was no mean feat, then, for Roosevelt, a mere Knickerbocker, to enter, by marriage or otherwise, the sanctified precincts of the Boston Brahmin Cabot Lees.

Roosevelt showered Alice, his “wayward, willful darling,” with the modern-day equivalent of thousands of dollars in gifts. They met on October 18, 1878, during Roosevelt’s second year at Harvard, and from thereafter so often did he ride the eight-mile round trip from Cambridge to Chestnut Hill that he lamed Lightfoot, his horse, and the next winter doubled down by purchasing a dogcart, the 1870s equivalent of a roadster. Delirious when it appeared Alice might reject him, Roosevelt roamed the woods surrounding campus, shouting and threatening to duel rival suitors.

After two relentless years, Alice consented to marriage, an engagement that was announced on February 14, 1880. The marriage was a happy one and coincided with some of the most successful years of Roosevelt’s life. In four years with Alice, he “rose like a rocket,” becoming, at 23, the youngest person ever elected to the New York State Assembly and publishing his first major book, The Naval War of 1812. “I love to talk over everything with [Alice], from politics to poetry,” Roosevelt confessed to his diary.

So blissful was their life together that Roosevelt predicted by divinity and serendipity that their first child would surely be born on Valentine’s Day, 1884—four years to the day since their engagement. Instead, Alice gave birth to a daughter on February 12 and two days later died of kidney disease exacerbated by childbirth. To complete the tragedy, Roosevelt’s mother, Mittie, had died 11 hours earlier—on the same day, in the same house.

Roosevelt marked his diary with a large X and wrote, “The light has gone out of my life.” He quit the state assembly and fled to the Dakota Badlands, living what he would later call the “strenuous life” of a widower rancher and cowboy.

Following the death of Hathaway Lee, Roosevelt fled to the Dakota Badlands.

Written off by most as inconsequential in the life of Roosevelt, and without a historical record to prove otherwise, Alice was largely lost to history, supposedly the trauma Roosevelt purged deep within his soul or dislodged entirely. The late, great historian Edmund Morris is uncharacteristically cruel in describing Alice’s untimely death in his Pulitzer Prize–winning book, The Rise of Theodore Roosevelt (1979), as “perhaps more kind than terrible,” suggesting “in quitting him so early, she rendered him her ultimate service.”

This is where the story of Alice Hathaway Lee usually ends and Roosevelt’s new life, culminating in a stunning ascent to the White House as the youngest president in U.S. history, begins—until the opening of that box.

An archival record at Sagamore Hill National Historic Site, in Oyster Bay, New York, noted that the box, which Roosevelt kept his entire life, contained the “hair of Alice Lee,” and, indeed, what first appeared when we lifted the clasp and at last opened the box was a keepsake most parents then and now will recognize.

There were three small locks of hair. The first was a brown lock, tied with a small white cord, which was clipped from Alice Lee at the age of two weeks. Another brown ringlet was clipped when she was a year old. The third, slightly lengthier brown-blond lock is accompanied by a photo of Alice and a note in the distinctive handwriting of Alice’s mother: “Alice Lee’s hair cut when she was 8 or 9 years old.”

Unmistakably, there was something else in the box. Under a flap, almost hidden from view, was another, fourth object, this one much larger than the rest. As we opened the flap, 14 inches of long, wavy, dark golden blond hair appeared in full view. Resting atop the ponytail-size hair was a note, this time in Roosevelt’s own hand, reading: “The hair of my sweet wife, Alice, cut after death.”

The box containing locks of Hathaway Lee’s hair.

Theodore Roosevelt preserved his sweet wife’s hair, a macabre if common keepsake of the Victorian era, when the physical remembrances of lost loved ones were scant. Roosevelt’s memories of Alice were confined to his private diaries, but this keepsake was kept hidden from Edith, Roosevelt’s beloved second wife and onetime rival of Alice for his hand.

“I so wonder who my wife will be!,” Roosevelt mused in his diary just months before encountering the enchanting Alice for the first time. “‘A rare and radiant maiden,’ I hope”—quoting a phrase from Edgar Allan Poe’s poem “The Raven.”

It is, at the very least, curious that a young Roosevelt described his yet undiscovered and barely even imagined yet intensely wished-for future wife with the words Poe used to describe a lover, particularly given the accent in the poem on her being dead—extant “nevermore.”

This new discovery, which no biographer past or present has noted, argues that Roosevelt did not expel Alice from his soul. On the contrary, he made certain that a token of her physical self would remain with him forever. Nevermore would Theodore Roosevelt see and feel his rare and radiant maiden. Yet she would never leave his heart, his mind, his memory.

Edward F. O’Keefe won a Primetime Emmy for his work with Anthony Bourdain and currently serves as the C.E.O. of the Theodore Roosevelt Presidential Library, now under construction in the Badlands of North Dakota