An additional consequence was a steady flow of the precious metals to the Orient, inasmuch as European wares did not move eastward to an extent that could compensate for the exchange value of Indian luxuries. Were it only because of the unfavourable balance of trade, the Western World grew more and more eager to escape from this ruinous and degrading control, until at length forcible measures were taken to bring it to an end. The Crusades were not exclusively or mainly (as romanticists are apt to believe) the outcome of an endeavour to liberate the Holy City from the grip of unbelievers. The primary object of the first military coalition of Christian Europe was to break through the Mohammedan barrier across the Red Sea and thus free the trade routes to the East. Since the attempt failed, since Egypt could not be torn from the Moslem grasp and Islam continued to bar the way to the Indies, there necessarily arose an urgent desire to discover a new route to Hindustan, which would be delivered from the menace of the followers of the Prophet.

The boldness which inspired Columbus's voyages to the west, Bartholomeu Dias's and Vasco da Gama's expeditions to the south, and John Cabot's voyage from Bristol to Labrador, was, above all, the outcome of the long-repressed yearning to free the West from Mohammedan arrogance and to discover an unhampered route to the Indies on which Christian trade would no longer be shamefully subject to Islam. Always when important discoveries or inventions are made, those who make them believe that they do so under stress of moral impulsion, whereas often at bottom material motives are at work. No doubt kings and their counsellors would have been impressed by the ideas of Columbus and Magellan, would have been friendly to these explorers' schemes for ideal reasons. But they would never have opened their purse-strings freely, nor would merchant adventurers have backed the hazards to the extent of equipping fleets, had there not been good prospects of discovering a new trade route to the Indies, the land of gold and spices. Throughout that age of amazing discoveries and explorations, the driving force was the mercantile spirit. Behind the hero stood the trader. Alexander apart, the first impulse to the European invasion of India was thoroughly mundane. The quest for spices began it.

Wonderful things happen in history when the genius of an individual coincides with the genius of the times, when one man perspicaciously grasps the creative yearning of his age. Among the countries of Europe, Portugal, while in prolonged and splendid struggles she had thrown off the Moorish yoke, had not yet found an opportunity of fulfilling her part in Europe's mission. Though her victory had definitively established her independence, the fine energies of a young and passionate nation lay fallow; the natural will to expansion proper to every rising people had found no outlet. Possibilities of landward extension were restricted by the Spaniards, friends and brothers though these were; so that for a small and poor country the exclusive possibility of enlargement and colonisation lay on the sea.

At first sight, Portugal's situation seemed most unfavourable. According to the Ptolemaic system of geography (dominant throughout Europe from the end of the second century until the close of the Middle Ages), the Atlantic Ocean, whose rollers broke unceasingly on the Portuguese coast, was an endless and non-navigable waste of waters. No less un-navigable, declared Ptolemy in his map of the world, was the southern route along the African coast. It was impossible, taught the Alexandrian geographer whose authority was supreme at all the universities, to live at or near the Equator. Neither animal nor plant could endure the vertical rays of the sun. Uninhabitable sandy deserts extended to the South Pole. There was no possibility of circumnavigation, since Africa continued without a breach into the Terra Australis. In the view of medieval geographers, Portugal, lying beyond the Mediterranean, the only navigable sea, was in the worst possible position among the maritime nations of Europe.

It became the life purpose of a prince of Portugal to prove the possibility of what had been declared impossible, to attempt, in accordance with the words of the Bible, to make the last first. What if Ptolemy, though a leading geographical authority, had been mistaken ? What if this Atlantic Ocean, whose mighty waves brought to Portugal's coast strange woods which must have grown somewhere, was not endless after all, but led to new and unknown lands ? What if Africa were habitable south of the Equator ? What if the Alexandrian sage had blundered when he declared there could be no seaward route to the south of this unknown continent, that there was no marine means of communication with the Indian Ocean ? If Ptolemy had been wrong, Portugal, precisely because situated in the extreme west of Europe, would be the predestined starting-point of all voyages of discovery. Portugal would command the nearest route to the Indies; was not excluded from possibilities of successful navigation, but was privileged in that respect above all the nations of Europe.

This wish-dream, this determination to transform little Portugal into a sea power and to make of the Atlantic Ocean (hitherto regarded as an impassable barrier) a new trade route, became the leading idea of the Infante Enrique, whom history both rightly and unrightly has called Prince Henry the Navigator. Unrightly because, apart from a short voyage on a warship to Ceuta, Henry of Portugal never set foot upon a ship; and no book, no nautical treatise, no map penned by him has come down to us. Yet he is justly styled the Navigator, for he devoted all his wealth to furthering navigation. Having won his spurs in early youth in the Moorish wars during the siege of Ceuta (1415), one of the richest men in the country, son of John I of Portugal (surnamed the Great) and grandson of John of Gaunt, he could have indulged his ambition by aspiring to the most brilliant posts, for he would have been made welcome at any of the courts of Europe, and England offered him high military command. Being, however, an eccentric and an enthusiast, he preferred a life of creative solitude. Establishing his headquarters at Sagres, a small seaport at the south-western extremity of Portugal, near Cape St. Vincent, he erected there an observatory, and directed thence his exploring expeditions.