The well-known story of King Leopold II of Belgium’s violent theft of what’s now the Democratic Republic of the Congo is told by Adam Hochschild in his seminal 1998 book, King Leopold’s Ghost. But there’s another, lesser-known narrative, a footnote linked to the seeds of Leopold’s initial colonial ambition, which caught my attention four years ago.

In 1879, Leopold dispatched four Asian elephants and their mahouts from India, a region which had a tradition in working elephants, to Africa, which did not. Leopold’s ambition was to reach Lake Tanganyika—then a threshold of Congo’s so-called Ivory Frontier—and start an elephant-training operation using the Asian elephants to test a new form of transport in Europe’s Scramble for Africa, aimed at extracting its valuable resources, including ivory and rubber.

Belgium’s King Leopold II.

“A touching tale, if all were known,” remarked a missionary who had stumbled across this forgotten expedition at the end of the 19th century. He described Leopold’s parade as a “strange prodigy” of men carrying an agenda they didn’t fully understand or, in their duplicity, chose not to disclose. “Stuck high on the elephant’s back, you have four white men who symbolize the coming struggle for supremacy,” the missionary continued.

I felt a beckoning in his line if all were known, as if there were more to uncover. The missionary’s account drew me into the absurdity of Leopold’s endeavor, manifested in the image of Europeans on top of Asian elephants marching into the heart of Africa to inspire and demand deference. But the more I dug into the story, the more curious the context that emerged—including a thriving 19th-century trade in exotic wildlife.

An Englishman called Gerald Waller emerged as Leopold’s proxy procurement officer, his enthusiastic correspondence revealing how many ways there were to buy an elephant in 1879, be it Asian or African—if only stocks would last. Waller started by knocking on the door of the British zoologist Frank Buckland, a man also known for eating exotic animals at “zoophagical banquets,” serving all kinds of meat, from rhinoceros pie to elephant trunk.

Elephants approaching Lake Tanganyika, from the mid-19th-century journals of David Livingstone.

Waller also tried Charles Rice’s London emporium, but despite the promise of “Zoological Gardens, Menageries & Aquariums supplied on the shortest notice,” Rice’s single African elephant in 1879 was still too young—a three-year-old, which would have had to be ridden astride, like a horse.

Charles Jamrach, another leading importer of exotic animals, kept a menagerie near London’s docks—a stinking, noisy venue full of “chirpings and cooings and growlings innumerable,” as one visitor described it, as well as sulking Andean condors, lions, and rhinos lurking in dens. Jamrach had experience with importing young African elephants that might suit Leopold’s purposes—he later boasted how he’d walked 18 of them through the streets of London from his ship, “like ordinary cattle”—but Jamrach also had a reputation for being expensive, selling pet rhinos for 500 pounds apiece (the equivalent of $53,000 today).

So Waller turned to the Germans instead, specifically the Hamburg-based wildlife dealer Carl Hagenbeck, who had recently trained five African elephants. Unfortunately for Waller, this, too, proved a dead end—Hagenbeck’s stock was already promised to the Berlin Zoo. Shopping for elephants, it turned out, wasn’t going to be easy.

The thriving circus business was also driving up prices. In source markets, in India and Burma, an increase in demand for healthy working elephants was inflating the cost by up to 200 percent compared to a few years earlier.

Eventually, Leopold’s four elephants—a stately female called Pulmalla, or “Flower Garland”; Sosankallim, meaning “Budding Lily”; and two tusked bulls—were secured from an elephant stud at Pune, an Indian hill town with a military garrison where the British Raj retreated each monsoon from the muggy heat of Bombay.

In Pune, the animals’ work had been nothing much more than ceremonial—they’d wallow in the river, enjoy the shade of the banyan trees, deliver the occasional postbag. Their African commission couldn’t have been more different. On May 31, 1879, the animals were swum from ship to shore near Dar es Salaam to commence their bewildering journey—an 800-mile-plus expedition packed with lost history, forgotten voices, and imperial greed.

Sophy Roberts is a contributor to the Financial Times and Condé Nast Traveler and the author of several books. She lives in the U.K.