By the early 19th century, the ice-covered mystery at Earth’s southernmost latitude captivated the imagination of scientists across the United States and Europe. Was it an open sea? A continent? An archipelago? Though reports described harsh weather and frigid conditions, many geographers called the region Terra Australis Incognita, Latin for “the Unknown Southern Land.”

In a quest to explore Terra Australis and the Pacific Ocean, U.S. Navy Lt. Charles Wilkes set out from Norfolk Navy Yard in August 1838 with nearly 350 men aboard six vessels. He returned home four years later having “made discoveries that would redraw the map of the world,” writes author Nathaniel Philbrick in Sea of Glory: America’s Voyage of Discovery, The U.S. Exploring Expedition, 1838-1842. 

In circumnavigating the globe, Wilkes charted new land in the Pacific and beyond, and while he didn't discover Antarctica, he mapped 1,500 miles of its eastern coastline and proved it was a continent. Yet Wilkes’ legacy is largely forgotten to history—mired in conflict and overshadowed by other voyagers.

“There was a narrative to be told, in which [Wilkes] would loom much larger. But because of his personal failings, and his lack of a media or public relations around him, in a modern sense, his story dropped from public notice,” says Gillen D’Arcy Wood, author of Land of Wondrous Cold: The Race to Discover Antarctica and Unlock the Secrets of Its Ice and professor at the University of Illinois Urbana-Champaign.

British explorer James Cook crossed the Antarctic Circle during a voyage in the 1770s, but failed to reach the territory’s mainland. His descriptions of harsh Antarctic conditions largely deterred expeditions in the years that followed. By the 19th century, explorers had already documented several large continents in the Northern Hemisphere and increasingly began questioning what existed at the bottom of the Earth. 

“[European scientists] reasoned there must be some balancing continental mass in the Southern Hemisphere,” Wood says. “But there were just as many proponents of an open sea.”

Some also thought Antarctica might be an archipelago, while others believed in a hollow-Earth theory, in which you could enter the interior of the planet through access points in the North and South Poles.

During Andrew Jackson’s presidency, the United States began planning an expedition to assert its naval presence in the Pacific, driven by both commercial and scientific interests.

But the global voyage, authorized by Congress in 1836, was mired in political infighting from the start. Some naval leaders doubted the United States was capable of carrying out such a massive endeavor. Conflicts also erupted over who would lead the expedition, and delays and equipment issues became evident. Wood describes the situation as “Washingtonian political machinations at its worst.” Many, including the press, referred to it as “The Deplorable Expedition.”

“So began the blame-shifting and the finger-pointing,” Wood says. “One of the problems was that, because there was a scandal around the expedition and uncertainty, all of the officers of the requisite seniority turned it down.” 

Amid several dissenting voices, naval officials settled on 40-year-old Charles Wilkes to lead the expedition. Wilkes, who had joined the navy as a midshipman in 1818 and risen to the rank of lieutenant, had a reputation as a skilled surveyor, despite lacking significant command experience.

Wilkes gleefully accepted the offer, and the U.S. Exploring Expedition—also called the Wilkes Expedition, or Ex. Ex. for short—began in 1838, with Wilkes aboard the flagship U.S.S. Vincennes. Joining him on the voyage were military personnel and a group of nine scientists and artists.

Over the next four years, Wilkes traveled roughly 87,000 miles, surveyed 280 Pacific islands and mapped 800 miles of Pacific Northwest coastline, as detailed in Sea of Glory. 

After reaching Australia in late 1839, Wilkes and his squadron sailed toward Antarctica. The U.S. expedition coincidentally arrived at around the same time, in January 1840, as the expedition led by Jules Dumont d’Urville of France, who placed a French flag on an offshore island before heading back north. 

Disregarding his medical staff’s advice and the brutal Antarctic conditions, Wilkes pressed onward and mapped the 1,500 miles of east Antarctic coastline, later dubbed Wilkes Land. He became the first explorer to recognize Terra Australis had continental dimensions, with a glacial cap covering its landmass.

“The formation of the coast is different from what would probably be found near islands, soundings being obtained in comparatively shoal [shallow] water; and the colour of the water also indicates that it is not like other southern lands, abrupt and precipitous,” Wilkes later wrote.

Wilkes went on to chart land in the Pacific Northwest, including the Oregon Territory and Puget Sound region. His expedition returned to the United States in 1842. It had endured the loss of two ships and 28 officers and crew members but also amassed a heap of scientific observations, charts and specimens. Wilkes went on to publish the multi-volume Narrative of the United States Exploring Expedition.

Why are Wilkes' scientific achievements often overlooked in the annals of history? First, Wilkes was a “toxic commander” whose “erratic behavior” damaged morale, Wood says.

“He would take a prejudice against any officer for any reason and bully them and marginalize them, or he’d send them home,” Wood says.

The expedition also ended the same way it began: shrouded in turmoil. Wilkes faced multiple court-martials upon his return home and concurrently brought charges against several officers. For example, Wilkes was accused of illegally attacking and murdering Fijian natives (to which he was acquitted) and of illegally flogging officers, a charge that led to his conviction and a public reprimand. Wilkes’ European rivals—and some U.S. naval officers—accused him of fabricating his charts of Antarctica, though some historians later vindicated Wilkes of these claims, arguing human error was the more plausible explanation.

Wilkes’ story also became lost in history, Wood says, because Britain was better equipped than the United States to publicize (and control) the narrative of its own James Clark Ross, who reached Antarctica in the early 1840s, after Wilkes. Ross went on to receive international acclaim.

“Essentially, Wilkes and his achievement just sank from trace,” Wood adds.

Despite his controversies, Wilkes advanced to the rank of rear admiral—even after his career faced another setback during the Civil War, when he was again court-martialed and found guilty on multiple charges. He was ultimately suspended from the Navy and passed away in 1877. His scientific discoveries helped lay the groundwork for later scientific research in Antarctica, which surged in the late 19th and early 20th centuries and spurred continued international cooperation on the continent.