If historians can trace the roots of globalisation back to archaic times, it is conventional now to see the early modern age as the critical accelerator in the creation of an interconnected world – the moment when European navigators linked the oceans together and inaugurated what we in the West have come to call the Age of Discoveries, or the Era of Columbus. Yet the historian Arnold Toynbee pointed out that it might more justly be labelled the Era of Vasco da Gama. The Portuguese were in many respects the true pathfinders in the development of globalisation. What were the forces that impelled this leap forward by pioneers on the edge of the Iberian Peninsula? With the hindsight of the 21st century, it is presumptuously Eurocentric to talk about the discovery of the world that got under way in the late 15th century. The great civilisations of the East needed no discovering. Rather, this revolutionary moment was more about ending the isolation of Europe. Europeans probably knew less about India and China than did the Romans. By the late Middle Ages almost all their information, derived from Marco Polo, was 200 years out of date. From a global perspective, Europe was an impoverished backwater imprisoned by geography and affected by a sense of claustrophobia. It was barricaded at the eastern and southern shores of the Mediterranean by an Islamic world viewed as an implacable enemy. The Mongol Highway that had carried Polo to China had collapsed. The lock seemed to have finally snapped shut with the fall of Constantinople to the Ottomans in 1453. All access to the highly desirable goods of the Orient had to be resentfully conducted through Islamic middlemen at exorbitant prices. European bullion drained away to pay for it.

At its western edge the continent was similarly confined by the Atlantic Ocean, ‘the great green sea of darkness’ as the Arabs called it, an immense and frightening expanse of violent and unknown ocean controlled by a hostile fixed-wind system. Europeans were also largely still in thrall to the conceptual worldview of Ptolemy, the classical geographer of the 2nd century AD, who posited the idea that Africa was endless and simply wrapped around the earth, making the Indian Ocean an enclosed lake.

Yet with the repeated failure of crusade, the Atlantic Ocean offered the only escape. There was growing discussion during the latter half of the 15th century as to the possibility of a finite Africa. The Portuguese were the best placed by geography and circumstance to test this notion. Portugal was small and impoverished. Its population hardly measured a million, out of a total in the Iberian Peninsula of some eight million. It had few natural resources, was too poor to mint its own gold coins and it was stifled by its Iberian rival, Castile, from access to the Mediterranean trade zone. Its one asset was a long Atlantic coast line, some good natural harbours, and the skills of open-sea sailing that its inhabitants had been forced to develop as fishermen and traders.

The drivers for Atlantic exploration were a clutch of interlocking geopolitical, religious and economic ideas. The Portuguese knew that somewhere south of the Sahara Desert lay sources of gold. Though they had only the dimmest of notions about the existence of the gold mines of the Senegal River, glimpsed on the early 15th-century maps of Jewish cartographers, the possibility of outflanking the Islamic barrier and accessing the wealth of continental Africa directly was a powerful incentive. Alongside this went a military idea of some antiquity. The desire in Christian Europe to destroy Islam had long conjured a strategy for outflanking the Muslim world and cutting off its sources of wealth from behind. Linked to this was an element of wish fulfilment: the enduring notion of the existence of a semi-mythical Christian king, Prester John, with whom Christian crusaders could unite to vanquish the forces of the anti-Christ.

All these elements, material and religious, practical and mystical, fed into the Portuguese exploration of Africa during the 15th century, initially under the figure who has passed into the bloodstream of history as Henry the Navigator, then through determined royal successors. For 60 years Portuguese navigators worked their way down the west coast of Africa. The breakout from the Atlantic, finally achieved by Vasco da Gama’s expedition to India in 1497–99, was the work of decades of knowledge acquisition about the pattern of the ocean’s winds. At the same time, in competition with Castile and through the offices of the papacy, the European pioneers forged a new geopolitical idea: the concept of a mare clausum (closed sea). The Atlantic spaces were to be carved up between the Iberian rivals into zones of exclusive influence and monopoly trading.

Globalisation as we see now on an almost daily basis is disruptive, and the Portuguese arrival in the Indian Ocean caused immediate jolts to a trade system that was millennia old. The empires of the monsoon comprised a vast commercial trading commonwealth of great antiquity that shifted goods from Canton to Cairo through a complex set of exchanges in the hands of many participants, cultures and religions. It was a comparatively peaceful free trade zone with a measure of accommodation between Islam, Hinduism and Buddhism. ‘God’, it was said, ‘has given the sea in common.’ There was piracy, but no protectionist war fleets, and crucially no ship-borne gunpowder weapons.

The Portuguese entered this world as a player outside the game with an asymmetrical set of goals, technologies and worldviews. They carried with them fast-firing bronze cannon, unmatched in the Indian Ocean, the intention to monopolise the spice trade, and a keen sense of religious mission – ideals of crusade and conversion in a space of comparative tolerance. In addition, their long apprenticeship of exploration down the African coast had equipped them with high level skills of knowledge acquisition, navigation and cartography that allowed them to comprehend the world of the Indian Ocean at great speed. Within a decade they had a good understanding of how the sea worked – the rhythm of its monsoons, its trade hubs, choke points, political affiliations – and had developed a geopolitical strategy for dominating it. One by one they acquired by siege and treaty the critical nodal points that controlled the trade of the sea, from Mozambique on the Swahili Coast to Malacca on the Malay Peninsula, which served as the lynchpin of trade with China and the Spice Islands. The Portuguese in the Indian Ocean were too few in number, never totalling more than 3,000 during the 16th century, to construct land empires; their policy was to create an empire of forts and bases held together by mobile sea power with the express aim of monopolising the spice trade.

Within the tight court circle of the Portuguese king, Manuel I, this commercial plan was the servant of a second strategy – the crusading dream of outflanking the Islamic world. By cutting the supply of spices and oriental wealth that fed the Mamluk dynasty in Cairo and the merchants of the Arabian Peninsula, Manuel hoped to bring the Islamic world to its knees. He envisaged a pan-European pincer movement, calling on the kings of Europe to launch a simultaneous Mediterranean crusade. The most flamboyant aspect of this policy was the notion to link up with Prester John, finally identified as the Christian king of Ethiopia, and to sail up the Red Sea, capture the body of the Prophet Mohammed from Medina and hold it to ransom against the return of Jerusalem – a plan of breath-taking ambition.

Critical to this operation was the capture of Aden, which dominated the mouth of the Red Sea. Its failure in an attack by the governor of Portuguese India, Afonso de Albuquerque, in 1513 was the high-water mark of Manuel’s grand plan. The Mediterranean crusade never happened, and by the time that Portuguese envoys reached the Ethiopian highlands and presented themselves at the court of its Christian king, Dawit II, in 1521, it was also apparent that the African Christians were not the mighty and powerful allies of European imagination. Manuel’s grand strategy failed, and with it the ability to control the trade of the Indian Ocean. The spice merchants of the Islamic world outflanked European blockade. The Portuguese became just another player in the game, but their restless advance continued unabated. Explorers and merchants, often acting independently of royal authority, pushed further across the globe. After conquering Malacca at the tip of the Malay Peninsula in 1511, they reached the Spice Islands in 1512, landed in China in 1513 and Japan in 1543. In 50 years they had touched every continent on the planet, with the exception of Antarctica and Australia, although the possibility that they were the first to Australia remains open to speculation. In the process they tied the world together.

Unlike the Spanish, the Portuguese hardly aspired to large-scale territorial domination. Instead they created an empire of maritime linkages that became the model for its northern European successors, the Dutch and the English. After an initial and quite bloody entry into the Indian Ocean, it evolved into a commercial empire in the 16th century that stretched from South America to China and saw the start of a system that could exchange goods across hemispheres. Complex trading cycles developed. Goa became the commercial hub of the western Indian Ocean, shuttling goods and foodstuffs between East Africa, Hormuz at the mouth of the Persian Gulf and western India. Malacca became the axis of a second commodity exchange, linking Goa to Canton, the Spice Islands and Japan. Portuguese merchants cornered an intermediary market between China and Japan, old enemies that nevertheless required each other’s goods: Japanese copper and silver were exported from Nagasaki to Macao on Portuguese ships, in exchange for gold, silk and porcelain.

These mechanisms set in motion an interlocking set of long-range trades. A lens could travel from Germany to China, an elephant from Sri Lanka to Austria. A wealthy merchant in Portugal could order a dinner service emblazoned with the arms of Portugal from a Ming potter. Cloves that would be sold in Morocco made the journey from Ternate in eastern Indonesia, via Malacca, Cochin and Lisbon, and would be exchanged for wheat that would find its way to West Africa. Venetian glass beads and Flemish brass pans carried via Lisbon to West Africa might be exchanged for pepper, gold, slaves and monkeys that would be shipped back to Bristol, Antwerp and Genoa. All these commodities travelled in Portuguese vessels. Within the separate oceans, triangular trades developed. Goods circulated in the Atlantic Ocean between Portugal, West Africa and Brazil. Within the Indian Ocean and beyond, valuable trading cycles often never touched the mother country at all.

The effects of these widening contacts caused ripples across the world system. The Portuguese were major agents in substantial bullion flows. They shifted gold from West Africa to Brazil and were instrumental in the dissemination of Spanish silver across the world as far as China, and a price revolution in India. Technology transfers were a by-product of this commercial restlessness, bringing astrolabes and observatories to the Ming dynasty in China, firearms and pilot charts to Japan, and metal-working techniques from Benin to South America.

The long-distance interchange of commodities and technologies extended to plants and foodstuffs. As the connections between the farthest reaches of their empire grew stronger, deliberate experiments were made to transplant crops from one continent to another, sometimes by carrying whole plants, more often by taking seeds on their voyages. These initiatives made a major contribution to the dissemination of plant species, food supply and diet across the globe. They introduced spices from the East Indies to Brazil, returning cashews, peanuts and peppers to both China and India, to which they also introduced pineapples and tobacco. There was a significant species exchange across the Atlantic between Brazil and Africa: maize, cassava, cashews, sweet potatoes and peanuts travelled east on Portuguese ships, returning from the west coast of Africa with red peppers, bananas, and yams. From Portugal, vegetables, citrus fruits and sugar cane reached the New World. Rhubarb came to Europe from South China, satsumas from Japan. The American crops that they introduced to Africa, particularly maize and cassava, and those that they sent to China, altered and improved the diet of peoples across the world.

The journeys, cultural meetings and interactions between the Portuguese and other peoples created an immense quantity of information. The first century of their discoveries saw a successive stripping away of layers of medieval mythology about the world and the received wisdom of ancient authority – the tales of dog-headed men and birds that could swallow elephants – by the empirical observation of geography, climate, natural history, and cultures that ushered in the early modern age. In this process peoples from the farthest ends of the earth could see each other for the first time. If the Portuguese saw, they were also seen – variously as objects of curiosity, fear and wonder. The Sinhalese were perplexed by their endemic restlessness and their eating habits, declaring them to be ‘a very white and beautiful people, who wear hats and boots of iron and never stop in one place. They eat a sort of white stone and drink blood.’

The Japanese scrutinised the namban-jin – the southern barbarians (because they arrived via Korea) – and scrupulously illustrated their ships, their ballooning pantaloons and strange hats in comic detail, lampooning their mannerisms and their large noses. Across the trading world, images and artefacts of the other reflected a new trans-hemispheric awareness. Many of the cultures to which the Portuguese travelled came to produce hybrid works of art: the Madonna and child as Chinese figurines; carved ivory boxes from Sri Lanka mixing Hindu deities with representations of European kings and images from Albrecht Dürer; Portuguese nobles in palanquins in Goan art and their ambassadors in Mughal miniatures; Benin bronzes of Portuguese soldiers with muskets and crossbows, and carved salt-cellars topped by miniature European ships.

In this process of early exchanges the Portuguese were also propagators of mixed race and creole societies. They exported themselves. From their early years in India, it was apparent that there were too few of them – and they were almost exclusively men. There was no Mayflower-style emigration of a population. In Goa they quickly adopted a mixed-marriage policy with Hindu women, usually converted to Christianity. This convergence of the human gene pool had its dark side too. Portuguese merchants on the west coast of Africa invented the Atlantic slave trade. From the ominous fort of Elmina in modern Ghana, they began the industrialised deportation of tens of thousands of black Africans to work in the gold mines and plantations of expanding Brazil. Half died in transit. Over a period of 300 years, somewhere between three and five million people were forcibly removed to South America by the Portuguese and their Dutch and English successors – a colossal fact of involuntary migration and the genetic mixing of the world’s peoples.

The slave ships were also an inevitable breeding ground for disease, but the wider mobility of the Portuguese made them, like the Spanish, unwitting contributors to the spread of pathogens around the world. Gama’s ships and their successors may have introduced syphilis to India and beyond – to Timor, where it was referred to as the Portuguese disease, and to China. Like the Spanish, they carried with them into South America the diseases of Europe such as mumps, yellow fever and TB. Smallpox and typhus proved particularly devastating to the native peoples of the Amazon.

Portugal’s commercial dominance of large swathes of the world lasted little more than a century, but its influence much longer. The images, transmissions, and trades that it engendered left a significant and long-lasting influence on the culture, food, flora, art, history, languages, and genes of the planet, together with dark shadows – the exploitation, violence and slavery that its colonial successors inherited. In the process they played a decisive role in the formation of our modern, globalised world with its complex of disruptions, threats and opportunities. The pathfinders in this process displayed a precocious sense of the potential benefits of the forces they had set in motion. Writing about the first decades of Portuguese exploration, the 16th-century historian João de Barros described a Portuguese governor of India addressing an Indian raja with the assertion that ‘the principal intention of his king Don Manuel in making these discoveries was the desire to communicate with the royal families of these parts, so that trade might develop, an activity that results from human needs, and that depends on a ring of friendship through communicating with one another.’ It was a prescient awareness of the origins and benefits of long-distance trade: the runaway train of globalisation that started with Vasco da Gama. At the same time, disruption left, and still leaves, its scars on human societies and economies. In the 1930s, during the last days of the ancient monsoon trades that had preceded the coming of the Portuguese, the captains of Arab dhows still mourned their passing and cursed the name of the Muslim pilot who had shown Vasco da Gama the sea route to India.

This essay by Roger Crowley was originally published with the title “The Portuguese: Pioneers of globalisation) in The Return of Geopolitics: Perspectives from the Engelsberg Seminar 2016, Axess Publishing, 2019.