Portugal Begins the Commercial Revolution, 1300–1517: Prince Henry, Da Gama and the Sea Route to India

A retelling of Durant's chapter on Portugal: the kingdom's early rulers, the tragedy of Pedro and Inês de Castro, independence at Aljubarrota, Prince Henry the Navigator and the voyages down the African coast, the rounding of the Cape, Vasco da Gama's arrival in India, Albuquerque's empire of trade, and the art and letters of Portugal's golden age.

Prince Henry the NavigatorVasco da GamaPortuguese Empire

~14 min read · Updated Oct 28, 2026

A Small Country with the Sea at Its Door

Little Portugal made itself, in this age, one of the strongest and richest countries of Europe by one natural advantage, its position on the coast, and by courage and a taste for great undertakings, and by nothing else. Founded as a kingdom in 1139, it took its settled form of government, language and culture under its best-loved ruler, Dinis, called "the Farmer," a statesman, reformer, builder, educator and patron of the arts who was also a practiced master of poetry and love.

His son Alfonso IV, after some precautionary killings, began a generous reign in which growing trade with England drew the two countries together politically, as it still does. Prudently, to strengthen the alliance with rising Castile, Alfonso arranged the marriage of his son Pedro to Constanza Manuel.

Pedro and Inês de Castro

Pedro married the princess but kept on loving Inês de Castro, who was herself of royal blood. After Constanza died, Inês stood in the way of a second marriage of state, and Alfonso, after long hesitation, ordered her killed (1355). Camões, who is counted as the Milton of Portugal, tells the famous story in his national epic, The Lusiads, painting the murderers as a bloodthirsty band whose swords were stained against her white breast and on whom divine vengeance had not yet fallen.

When Pedro came to the throne two years later he took his revenge. He put the murderers to death, exhumed the body of his beloved, crowned her as queen and had her reburied with royal honors, and ruled with a severity that sprang from the tragedy.

Fernando, Leonor and Aljubarrota

Another love story, less exalted, broke up the next reign. Fernando I lost his heart to Leonor, wife of a nobleman, broke his engagement to a Castilian princess, and married her against the objection of her husband and the scandalized Church. After his death (1383) Leonor became regent, made her daughter Beatrice queen and married her to John I of Castile.

The Portuguese rebelled at the prospect of Castilian rule. The assembly at Coimbra declared the Portuguese crown elective and chose John, son of Pedro and Inês. Castile resolved to place Beatrice on the throne by force. John at once raised an army, called for 500 English archers, and defeated the Castilian army at Aljubarrota on August 14, 1385. The Portuguese still celebrate that day each year as the day of their independence.

John I and the House of Aviz

John, called "the Great," began a forty-eight-year reign that brought the house of Aviz to the throne, where it remained for two centuries. He reorganized the administration and reformed law and the courts. Portuguese became the official language and Portuguese literature began. Here, as in Spain, scholars wrote in Latin until the eighteenth century. But Vasco de Lobeira wrote in the vernacular a chivalric romance, Amadis of Gaul (about 1400), whose translations became one of the most popular secular books in Europe.

National art found splendid expression in the church of Santa Maria da Vitória at Batalha, built by John to commemorate Aljubarrota. In size it rivals the cathedral of Milan, and in the rich intricacy of its buttresses and ornamental pinnacles it matches Notre-Dame of Paris. In 1436 a chapel of delicate design and decoration was added to hold the bones of the "bastard king."

Henry the Navigator

His sons also brought him honor. Duarte succeeded him and ruled almost as well; Pedro drew up a code of laws for the country; Henry the Navigator began the commercial revolution that was destined to change the map of the globe. When John I took Ceuta from the Moors (1415), he left the twenty-one-year-old Henry as commander of that important strategic base across the strait from Gibraltar.

Muslim accounts of Timbuktu, Senegal, and of gold, ivory and slaves on the west African coast stirred the ambitious young man, and he resolved to explore those regions and add them to Portugal. The Senegal River, of which he was told, might flow westward toward the sources of the Nile and the Christian kingdom of Abyssinia. If so, a sea route could be opened through Africa to the Red Sea and thus to India. Then Italy's monopoly of eastern trade would be broken and Portugal would become a great sea power. The conquered lands would all become Christian, Muslim Africa would be enclosed by Christian states north and south, and the Mediterranean would be safe for Christian commerce. Henry did not intend to find a way around Africa, but that was the historic result of his work.

Sagres and the Islands

About 1420 Henry founded at Sagres, at the southwestern tip of Portugal and of Europe, an informal institute for gathering information and organizing voyages. For forty years he and his associates, who in the book's account included Muslim and Jewish astronomers and mapmakers, collected and studied the reports and descriptions of travelers and sailors, and sent small ships, driven by sail and oar and carrying no more than thirty to sixty tons, to probe the dangerous sea.

One of Henry's captains discovered Madeira in 1418 (the book's date), which Genoese sailors had reached seventy years before and then forgotten. Portuguese colonists developed its resources, and soon its sugar and other products repaid the cost of settling it, which made the crown more willing to grant Henry's requests for money and credit. Henry had seen the Azores on an Italian map of 1351, and he commissioned Gonçalo Cabral to find them. This was done, and from 1432 to 1444 these precious sea jewels one after another adorned the Portuguese crown.

Down the African Coast

But Africa drew Henry most and stirred his ambition. Catalan and Portuguese sailors had explored the west coast as far as Cape Bojador (1341–1346, in the book's dating). There the great bulge of the continent into the Atlantic discouraged sailors from looking for a way south, and they turned back to Europe, excusing themselves with frightening tales of fierce natives and a sea so thick with salt that oars could hardly cut it, and assured their listeners that any Christian who passed Bojador would turn black.

Captain Gil Eanes returned to Sagres in 1433 with such excuses; Henry ordered him out again and told him to bring back clear, accurate knowledge of the forbidden lands and seas beyond Cape Bojador. So Eanes sailed some 2,400 kilometers beyond it (1435, the book's figures) and was astonished to find, in a region that Aristotle and Ptolemy said must be burnt desert under the sun, everything green and fertile. Six years later Nuno Tristão went still farther, to Cape Blanco, and brought back several strong Africans who were baptized at once and enslaved.

Feudal lords put such captives to work on Portuguese estates, and the first important result of Henry's labors was the opening of the African slave trade. Now the prince had new financial backing. His ships were officially sent to explore and spread the faith, but in practice they brought back gold, ivory and slaves. In 1444 Captain Lançarote brought home 165 captives, set to work on the lands of the Order of Christ. A Portuguese chronicler of the time describes their capture with the self-righteous piety of the age, thanking God for victory over "the enemy."

By 1448 more than 900 African slaves had been brought to Portugal. The author adds that North African Muslims had led the way in the slave trade, and that African chiefs themselves bought slaves from the Portuguese and paid in gold and ivory. In the hands of such human beasts, he writes, man became a commodity for buying and selling.

Toward the Cape

In 1445 Dinis Dias reached the high headland called Cape Verde; in 1446 Lançarote explored the mouth of the Senegal; in 1456 Cadamosto discovered the Cape Verde Islands. In that year Prince Henry died, but his work, driven by the momentum he had given it and by its economic profits, went on. João de Santarém crossed the equator (1471); Diogo Cão reached the Congo (1484).

Finally, half a century after Henry's first expedition, Bartolomeu Dias fought his way through storms and shipwrecks around the southern tip of Africa (1486, the book's date). He was glad to see that he could turn east; India lay almost within reach. But his exhausted and anxious men forced him to turn back. Mourning companions whose ships the stormy sea had broken, Dias named the southern headland the Cape of Storms. King John II, who saw India beyond that bend, renamed it the Cape of Good Hope.

Vasco da Gama Reaches India

Neither Dias nor the king lived to see the dream of an all-water route to India, which now excited all Portugal, realized. In 1497 King Manuel, envious of the wealth and honor Columbus had won for Spain, commissioned Vasco da Gama to sail around Africa to India. Storms forced a roundabout route, and after 137 days and 8,000 kilometers by sea he reached the Cape of Good Hope. Then, through hundreds of dangers and thousands of hardships, another 178 days and 7,250 kilometers brought him to Calicut, a key junction of east-west and north-south trade in Asia. There, on May 20, 1498, ten months and twelve days after leaving Lisbon, he anchored.

The moment he landed he was arrested as a pirate and barely escaped punishment. With admirable courage and eloquence he overcame the suspicion of the Indians and the jealousy of the Muslims and won permission to trade for Portugal. He loaded his ships with pepper, ginger, cinnamon, cloves, nutmeg and precious stones, and on August 29 left Calicut for the hard year-long voyage to Lisbon. At last the Portuguese had found a way to India, freed from the heavy costs of transferring cargo from ship to ship, from tolls and levies, and from the hardships of the old land and sea routes through Egypt, Arabia or Persia. For a century the economic results of this discovery were more useful to Europe than those of the discovery of America.

Brazil and the Atlantic

Proud of having reached the real India, while Spanish sailors had mistakenly landed on islands in the Caribbean, Portugal made no effort until 1500 to find a western passage. But in that year Pedro Cabral, driven off course on his way to India, reached Brazil by accident, and in the same year Gaspar Corte-Real discovered Labrador. In 1503 Amerigo Vespucci, sailing under the Portuguese flag, reached the Rio de la Plata and Paraguay, and in 1506 Tristão da Cunha discovered the South Atlantic island that now bears his name. Portuguese rulers saw little profit in Brazil, while every cargo from India filled the royal treasury and the pockets of merchants and sailors.

Albuquerque's Empire of Trade

Because commerce then always needed the protection of armies, the Portuguese state took the new trade under its full control. Muslim merchants had long since built bases of their own in India, and some powerful Indian rajas allied with them against the Portuguese. War, trade, money and blood mingled in the vast commercial revolution that had begun.

In 1509 Afonso de Albuquerque became the first Portuguese governor of India. In repeated wars with Muslims and Indians he took Aden and Hormuz on the Arabian side (as the book has it), Goa in India and Malacca on the Malay peninsula, and built Portuguese bases in them. From Malacca he brought home booty worth a million ducats (the book's figure). Thus for a hundred and fifty years Portugal was the undisputed master of European trade with India and the East Indies. Portuguese merchants extended their trading domain east to the Moluccas (1512) and rejoiced to find that nutmeg, mace and cloves of these "Spice Islands" were more pleasant and cheaper than those of India.

Albuquerque had an insatiable appetite for the world. He sailed into the Red Sea with twenty ships and proposed to the Christian king of Abyssinia that they dig a canal from the upper Nile to the Red Sea, diverting the river and turning Muslim Egypt into dry desert. Disorder forced him back to Goa, where he died in 1515. The next year Duarte Coelho opened the gates of trade with Cochin China and Siam, and in 1517 Fernão Pires de Andrade established trade relations at Canton and Peking (as the book puts it).

Lisbon, Letters and Art

The Portuguese empire, the first example of modern imperialism, had reached its greatest extent, and its only rival was Spain, for whom the discovery of America had opened the gates of such an empire. Lisbon became a thriving center of commerce where merchant ships from distant lands tied up. Merchants of northern Europe could buy most Asian goods here at the lowest prices, not at Venice or Genoa. Italy mourned the time when eastern trade was wholly its own. The Italian Renaissance, on which Columbus, Vasco da Gama and Luther had in one generation struck mortal blows, slowly lost its color, while Portugal and Spain, rulers of the open seas, became the pioneers of the fertility and flowering of the Atlantic countries.

In the shadow of this grandeur, literature and art flourished. Fernão Lopes spent twenty years writing his voluminous Chronicles (the book's dates are garbled), telling the history of Portugal with the charm of a story and a power of description that matches Froissart's. Gil Vicente opened Portuguese drama with small plays written for the court and scenes for public festivals (about 1500). A Portuguese school of painting, inspired and guided by Flemish painters, succeeded in developing characteristics of its own. In the great polyptych for the monastery of St. Vincent, Nuno Gonçalves (active 1450–1472) rivals Mantegna and even Van Eyck: its six panels are primitive in landscape and space, but the fifty-five individual portraits, the best of them of Henry the Navigator, show the power of his realism.

To keep alive the memory of Vasco da Gama's triumphant voyage, King Manuel, called "the Fortunate," commissioned João de Castilho to build near Lisbon, in the Gothic style of flame, the splendid and vast monastery of Belém (about 1500). Portugal had entered the golden age of its history.

Written & researched by Dr. Shahin Siami

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