The only impartial witness was the sun. For days, it watched as the strange object heaved up and down in the ocean, tossed mercilessly by the wind and the waves. Once or twice the vessel nearly smashed into a reef, which might have ended our story. Yet somehow—whether through destiny, as some would later proclaim, or dumb luck—it drifted into an inlet, off the southeastern coast of Brazil, where several inhabitants laid eyes upon it.

Above fifty feet long and ten feet wide, it was a boat of some sort—though it looked as if it had been patched together from scraps of wood and cloth and then battered into oblivion. Its sails were shredded, its boom shattered. Seawater seeped through the hull and a stench emanated from within. The bystanders, edging closer, heard unnerving sounds: thirty men were crammed onboard, their bodies almost wasted to the bone. Their clothes had largely disintegrated. Their faces were enveloped in hair, tangled and salted like seaweed.

Some were so weak they could not even stand. One soon gave out his last breath and died. But a figure who appeared to be in charge rose with an extraordinary exertion of will and announced that they were castaways from His Majesty’s Ship the Wager, a British man-of-war.

When the news reached England, it was greeted with disbelief. In September 1740, during an imperial conflict with Spain, the Wager, carrying some 250 officers and crew, had embarked from Portsmouth in a squadron on a secret mission: to capture a treasure-filled Spanish galleon known as “the prize of all the oceans.” Near Cape Horn, at the tip of South America, the squadron had been engulfed by a hurricane, and the Wager was believed to have sunk with all its souls. But 283 days after the ship had last been reported seen, these men miraculously emerged in Brazil.

They had been shipwrecked on a desolate island off the coast of Patagonia. Most of the officers and crew had perished, but eighty-one survivors had set out in a makeshift boat lashed together partly from the wreckage of the Wager. Packed so tightly onboard that they could barely move, they traveled through menacing gales and tidal waves, through ice storms and earthquakes. More than fifty men died during the arduous journey, and by the time the few remnants reached Brazil three and a half months later, they had traversed nearly three thousand miles—one of the longest castaway voyages ever recorded. They were hailed for their ingenuity and bravery. As the leader of the party noted, it was hard to believe that “human nature could possibly support the miseries that we have endured.”

Six months later, another boat washed ashore, this one landing in a blizzard off the southwestern coast of Chile. It was even smaller—a wooden dugout propelled by a sail stitched from the rags of blankets. Onboard were three additional survivors, and their condition was even more frightful. They were half naked and emaciated; insects swarmed over their bodies, nibbling on what remained of their flesh. One man was so delirious that he had “quite lost himself,” as a companion put it, “not recollecting our names…or even his own.”

After these men recovered and returned to England, they leveled a shocking allegation against their companions who had surfaced in Brazil. They were not heroes—they were mutineers. In the controversy that followed, with charges and countercharges from both sides, it became clear that while stranded on the island the Wager’s officers and crew had struggled to persevere in the most extreme circumstances. Faced with starvation and freezing temperatures, they built an outpost and tried to re-create naval order. But as their situation deteriorated, the Wager’s officers and crew—those supposed apostles of the Enlightenment—descended into a Hobbesian state of depravity. There were warring factions and marauders and abandonments and murders. A few of the men succumbed to cannibalism.

Back in England, the principal figures from each group along with their allies were now summoned by the Admiralty to face a court-martial. The trial threatened to expose the secret nature not only of those charged but also of an empire whose self-professed mission was spreading civilization.

Several of the accused published their sensational—and wildly conflicting—accounts of what one of them called the “dark and intricate” affair. The philosophers Rousseau, Voltaire, and Montesquieu were influenced by reports of the expedition, and so, later, were Charles Darwin and two of the great novelists of the sea, Herman Melville and Patrick O’Brian. The suspects’ main aim was to sway the Admiralty and the public. A survivor from one party composed what he described as a “faithful narrative,” insisting, “I have been scrupulously careful not to insert one word of untruth: for falsities of any kind would be highly absurd in a work designed to rescue the author’s character.” The leader of the other side claimed, in his own chronicle, that his enemies had furnished an “imperfect narrative” and “blackened us with the greatest calumnies.” He vowed, “We stand or fall by the truth; if truth will not support us, nothing can.”

We all impose some coherence—some meaning—on the chaotic events of our existence. We rummage through the raw images of our memories, selecting, burnishing, erasing. We emerge as the heroes of our stories, allowing us to live with what we have done—or haven’t done.

But these men believed their very lives depended on the stories they told. If they failed to provide a convincing tale, they could be secured to a ship’s yardarm and hanged.