What lurked below
Sea serpents, beach giants, boiling seas--ancient mariners feared them all
For the adventurers who first explored the ocean, known hazards were abundant enough. There was thirst, for one thing, along with hunger and scurvy, and hurricanes, mutinies, and shipwrecks. But before the Age of Discovery could even begin, mariners had to conquer the greatest obstacle of all: their dread of the unknown. Henry the Navigator, the 15th-century Portuguese prince who launched the era of exploration, called it "the shadow of fear" --the assortment of groundless qualms that kept ordinary Europeans securely on shore. Medieval minds envisioned sea serpents bigger than whales, an ocean that constantly boiled, and giants on the beach ready to wade in and grab a ship with one hand. "I marvel," Henry complained, "at the imaginings that have possessed you all."
One might marvel equally at what possessed Henry. Even as he scorned the superstitions of the masses, the monkish scholar who came to be regarded as a father of the modern world was embracing one of the Dark Ages' loopiest legends. Somewhere in Africa, he believed, there ruled the world's mightiest Christian, a hearty monarch known as Prester John. Europe's faithful had sought the priest king ever since the discovery of a letter in which the make-believe ruler claimed to outrank "in riches, virtue, and power all creatures who dwell under heaven." Henry clearly embraced the common view that Prester John's No.1 goal was to crush Islam, the spreading force that controlled a crescent from Morocco to Russia. That, too, was Henry's dream. If the king could be found, the prince reasoned, they together could start a crusade.
What passed for the best intelligence of the day suggested that the monarch lived in a mountaintop castle near a lake in Ethiopia. With North Africa in Muslim hands, no land route existed between Portugal and Ethiopia. If there was a sea route, it had to be around the bottom of Africa. But no one knew whether Africa had a bottom. Ptolemy believed Africa blended into Terra Incognita, a big landmass at the base of the globe. But another ancient scholar, Herodotus, declared Africa a peninsula that could be rounded. The best bet, Henry concluded, was to send a ship from Portugal down Africa's western shore.
To go that far down the Atlantic coast, however, would require a trip through what was deemed the gates of hell, a sandy projection of the western Sahara known as Cape Bojador. "Beyond this cape," said one of Henry's aides, "there is no race of men nor place of inhabitants." The cape, just south of the Canary Islands, endured in medieval minds as the most fearsome spot on Earth. South of its treacherous reefs and unmanageable currents lay the legendary Green Sea of Darkness, a scum-covered abyss brimming with reptiles that could swallow a ship. Closer to the equator, the sea boiled and the sun turned human skin black. Or so the sailors thought.
For a dozen years, Henry ordered roughly a ship a year to go beyond the cape. Each time, the mariners sailed south, eyed the cape's churning tides, and scurried home. Finally, the prince, who himself never sailed more than a few miles, gave one of his squires a bold order. "Strain every nerve to pass that cape," he told Gil Eanes. "You cannot find a peril so great that the hope of reward will not be greater."
Fearing Bojador's reefs and currents, Eanes took what seemed a riskier route. He skirted the cape, farther into the trackless ocean than any other Portuguese captain had ever ventured. In primitive minds, such a route might end with the ship sailing off the edge of the world. But Eanes kept westward until favorable winds enabled him to head east. After many days, he spotted land and went ashore. The land below Bojador, he found, was no worse than the land above it. And there was no Green Sea of Darkness.
Once the captain returned home and reported his feat, the imagined horrors of the sea began to dissolve. "Although the matter was a small one in itself, yet on account of its daring it was reckoned great," reported one of the captain's contemporaries. The voyage signaled the dawn of the Age of Discovery, as Henry swiftly ordered a series of expeditions beyond the once impassable cape.
The prince died a quarter century later, just as his captains were finding that the waters near the equator were warm but far from boiling. Henry never found Prester John. But he left a legacy far more durable: He tore down the wall of fear that barred the superstitious from the sea.
This story appears in the August 16, 2004 print edition of U.S. News & World Report.