In September 20, 1519, a fleet of five ships and 260 sailors set sail from the Spanish port of Sanlúcar de Barrameda, under the command of Ferdinand Magellan, a Portuguese mariner who had shifted his allegiance to Spain.

Magellan sought to find a westward route by water to the Spice Islands, a small archipelago in Indonesia that was the source of the nutmeg, cloves and other spices that Europeans coveted as flavorings and medicines. In accomplishing that, the expedition would circumnavigate the planet for the first time in human history. 

It was an audacious plan, one that involved sailing through thousands of miles of uncharted waters and finding a previously undiscovered passage through the Americas from the Atlantic Ocean to the Pacific. But Magellan, who believed that it was God’s will for him to succeed, was confident of success. 

The mariner was “an unparalleled example of navigational smarts, personal courage and indifference to hardship,” says Laurence Bergreen, author of the 2003 book Over the Edge of the World: Magellan’s Terrifying Circumnavigation of the Globe.

In the end, Magellan’s quest would cost him his life, and lead to the loss of all but one of his ships and most of his crew through death or desertion.

Here are some of the hazards that made Magellan’s expedition so treacherous, and how the explorer and his crew overcame some, but not all, of those obstacles.

Magellan didn't really know how to get to his destination.

Magellan initially tried to get Portugal’s King Manuel to authorize a voyage to discover a water route to the Spice Islands, according to Bergreen, but the king, who didn’t like him, nixed the idea. In frustration, he got permission from Manuel to pitch his plan elsewhere, and in 1517, he moved to Spain, where he lobbied officials on his idea. 

As a selling point, Magellan proclaimed his belief that the Spice Islands were located inside the Spanish realm delineated by the 1494 Treaty of Tordesillas, in which Spain and Portugal agreed to divide the non-Christian world between them. Magellan may actually have believed this, because he had a friend, Portuguese mariner Francisco Serrão, who had settled in the Spice Islands and wrote Magellan letters in which he placed the islands far to the east of where they actually were. 

Not only was Magellan mistaken about his destination, but he was even shakier about the route he would take to get there.

Magellan told Spanish officials that his plan was to sail along the eastern coast of South America until the land ended, and even showed them a globe to illustrate the route. Though he didn’t know the actual distance, he estimated that the round trip from the Spice Islands would take no more than two years.

But Magellan was vague about how he would get past the Americas. According to historian Jerry Brotton’s A History of the World in 12 Maps, a priest and author named Bartolome de las Casas, who witnessed the presentation, asked Magellan, “What will you do if you find no strait to pass into the other sea?” Magellan dodged the question. 

When Magellan finally crossed the Atlantic and got to  South America, finding the passageway turned out to be a lot harder than he had expected. One of his ships, the Santiago, was wrecked in a storm during the search and had to be abandoned. 

Magellan had to defeat a mutiny by some of his crew.

“The greatest danger that he encountered as a masterful navigator wasn’t the physical threats, the storms, or the natural hazards of sailing across a vast ocean,” Bergreen explains. “It was the often-rebellious group that he led, who came from many different countries and spoke different languages, and were often dead set against him and each other.”

“The captains who accompanied him hated him exceedingly,” wrote Antonio Pigafetta, a diplomat who kept a detailed diary of the expedition, which he later published as a book, Magellan’s Voyage Around the World. “I know not why, unless because he was a Portuguese, and they Spaniards.”

After a rough voyage across the Atlantic to Brazil, in which the fleet was battered by storms, the tensions increased when an officer on the Victoria, Antonio Salamón, was tried and executed by strangulation in December 1519 for sexually assaulting an apprentice seaman. The rumblings got worse. One of the captains, Juan de Cartagena, accused Magellan of being a Portuguese double-agent and sabotaging the mission. 

Cartagena and others hatched a plot to stage a mutiny and kill Magellan in April 1520. But according to an account by Portuguese historian Gaspar Correa, Magellan anticipated their treachery. When they tried to strike, an officer loyal to him pulled a dagger and cut the throat of mutineer Luis de Mendoza, whose corpse was then hung by his feet, “so they might see him from the other ships.” 

Magellan captured  the other conspirators, and their punishment was brutal. After one captain was beheaded, his body was drawn and quartered as an example of the price for disloyalty. Cartagena, who had tried to hatch a second plot, was left to starve on a small island off the coast.

Magellan’s severity might seem shocking today, but Bergreen says it wasn’t that unusual in his time. “Captains had life-and-death powers over their sailors, and they sometimes used it,” the historian explains.

But that didn’t quell all the dissent. The officers and crew of one ship, the San Antonio, managed to skip away in November 1520 and return to Spain.

The Pacific turned out to be a lot bigger than Magellan imagined.

In November 1520, Magellan finally discovered the Strait of Magellan, a natural channel that passes between the continent’s southern tip and the island of Tierra Del Fuego, he and his three remaining ships finally were able to sail into the ocean that he named the Pacific, because it seemed so serene. 

“He thought it would be a hop, skip and jump to circumnavigate the world and get to the Spice Islands, and then he would go home in triumph,” Bergreen says. “Of course, it didn’t turn out that way.”

Once the coast of South America disappeared, Magellan found himself out in the middle of an ocean that was vastly larger than he had imagined.

“He's crossing the Pacific, he's expecting to find land any day, not realizing that he’s  crossing the largest body of water on the planet,” Bergreen explains. 

 As the voyage stretched on, the ships’ crews had to subsist on a severely sparse diet and ration their water. The predicament even took its toll upon Magellan. “At one point, he got irritable, maybe because of the shortage of food, and started to become less reasonable,” Bergreen explains. The explorer realized that the maps he had been using were hopelessly inaccurate. Magellan abruptly threw them overboard. 

Magellan’s men were horrified. “They thought they were doomed without the maps,” Bergreen says. On the contrary, they actually were liberated. Without the charts, Magellan was forced to navigate by reading the signs in the ocean environment. He discovered the trade winds that blew across the Pacific, and his skill as a sailor—combined with the agility and maneuverability of his ships’ design—enabled him to speed his way across the Pacific before he and his men died of hunger and thirst.

Magellan's own overconfidence proved fatal.

When Magellan reached the Philippines in March 1521, he saw an opportunity to convert the indigenous people to Catholicism and place them under the authority of the Spanish King, according to Australian Catholic University scholars Kate Fullagar and Kristie Patricia Flannery.

Some local rulers, who saw advantages in an alliance with the Spanish, went along with Magellan. But Lapu Lapu, chief of the island of Mactan, refused. Magellan, who had experience as a soldier, decided to attack. On April 27, 1521, he and a small Spanish force of 60 armed men and 20 to 30 native allies attempted an amphibious invasion at dawn.

As Bergreen notes, Magellan assumed that his superior technology—muskets and armor—would overcome the indigenous people armed with wooden spears. That proved to be a fatal miscalculation. 

In Pigafetta’s account, the invasion force’s boats couldn’t get too close to shore because of rocks in the water, which forced Magellan’s men to jump into the water and try to wade to land. More than 1,500 warriors awaited them. Magellan’s musketeers and crossbow archers fired on the defenders, but in the chaos, they weren’t able to hit them.

“So many were the spears and stones that they hurled at us, that we could offer no resistance,” Pigafetta wrote. Magellan himself was shot through the leg with a poisoned arrow and had his helmet knocked off by attackers. He fought hard to survive, until a warrior slashed him in the leg with a cutlass, and he fell, allowing others to swarm over Magellan and hack and stab him to death.

Only one of Magellan's ships and 18 sailors made it back.

The Spanish suffered so many casualties that they had to abandon another of their ships, the Concepción, because they didn’t have enough men left to sail it. The two remaining vessels eventually made it to the Spice Islands in November 1521.

One of the two remaining ships, the Trinidad, was in disrepair and stayed behind for an overhaul. It was later captured by the Portuguese and eventually sank in a storm. That left only the Victoria to sail around Africa’s Cape Horn and head back along the west coast of Africa toward Europe.

On September 6, 1522, the Victoria reached the same Spanish harbor from which it had departed three years before. As Bergreen describes in his book. The Victoria’s tattered sails and battered, sun-bleached hull were evidence of the ordeal it had survived. Just 18 sailors out of the original 260 were left, and they were so weak from malnutrition and exposure that they had trouble walking or speaking.

The survivors did manage to bring back a load of spices, it was obvious that Magellan’s notion of establishing a westward route to Asia was too slow, costly and downright dangerous to be practical. 

How Magellan's expedition influenced history

Though the expedition might have seemed at the time like a failure, Magellan’s quest changed the world in critical ways.

By circumnavigating the globe, the expedition had extinguished any remaining doubts that the world was round, and it also showed that North and South America were separate continents from Asia and that our planet’s surface was mostly covered with water. 

It would take another half a century before English navigator, pirate and slave trader Sir Francis Drake matched the Magellan expedition’s feat by circumnavigating the globe in 1577-1580.

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