Especially in its later stages, this enterprise has become inseparable from the name of the Infante Dom Henrique. His desire for an island-realm off the African coast belongs in the context of the long-standing desire among European markets and courts to improve access to the sources of the trans-Saharan gold trade. The search may have begun as early as the mid-thirteenth century, for a plausible legend dates a Genoese expedition to Safi in 1253. In 1283 Ramon Lull reported a journey towards the land of the Blacks from Ceuta. The oasis of Sijilmassa is depicted along the trans-Saharan camel route that brought gold to Tlemcen in Giovanni di Carignano’s map of the early fourteenth century. The auriferous reputation of the west African interior was reinforced by reports of the pilgrimage to Mecca in 1324 of the Mansa Musa of Mali, whose prodigality caused inflation in Egypt; but no fourteenth-century attempt to outflank the trans-Saharan routes, and open direct communications by sea, was successful. Beyond the range of the Canary current, in latitudes where fresh water was hard to find on shore, the natural hazards of navigation seem to have been too formidable.
The land route continued to attract occasional explorers. In 1413, Anselme d’Isalguier was reported to have returned to Toulouse from Gao with a harem of Black women, though how he could have got so far into the interior of Africa no one knows. In 1447 the Genoese Antonio Malfante got as far as Touat. In 1470 the Florentine Benedetto Dei claimed to have been to Timbuctoo and observed there a lively trade in European textiles. From the 1450s to the 1480s, Portuguese merchants made efforts to cut across country from Arguin, via Waddan, heading for the same destination: at least they seem to have succeeded in diverting some gold caravans to meet them. It was obvious, however, that the intractability of the land route demanded a seaborne approach.
Three developments gradually made such an approach viable: the emergence of a highly manoeuvrable type of ship, equipped with lateen sails for enhancing headway against the wind; improved methods of storing provisions for long journeys — the construction, in particular, of water casks which could keep their contents in potable form for periods extending to months rather than weeks; and the establishment, beginning in 1439, of way-stations in the Azores where ships could stop to victual on the long run back from the west African bulge, via the deep Atlantic, to find the homebound westerlies.
Traditionally, the status of a breakthrough in the enterprise has been assigned to the rounding of Cape Bojador in 1434 by one of Dom Henrique’s ships; but, to judge from surviving maps and sailing directions of the fifteenth and early sixteenth centuries, the cape known by that name in the vague and fluid toponymy of the time was the modern Cape Juby, which had certainly been rounded many times before. ‘The cape-by-cape depiction of the building of empire’ is in any case an heroic distortion, originating in the narrative technique of the chronicler Zurara, who wrote to glorify the deeds of fellow members of Dom Henrique’s entourage. More significant were the achievements of expeditions led partly by Genoese navigators under Henrique’s patronage in the mid-145os, which reported the existence of the Cape Verde Islands, explored the lower reaches of the Gambia and Senegal rivers and established contact with outposts of the empire of Mali. These were genuinely unprecedented achievements in exploration. They produced, moreover, reports written by a Venetian participant, Alvise Da Mosto, whose observations of the people and environment of the Senegambia region were unsurpassed in vividness, among explorers’ accounts, until the writings of Columbus.
After Henrique’s death in 1460, explorers seem to have paused, presumably deterred by lack of patronage and the lee shores around the turn of Africa’s bulge. In 1469, the initiative was revived by the grant of the right of exploration to Fernao Gomes. He commissioned voyages which added some 1,200 miles of coastline to the area navigated by Portuguese ships and extended the range of mapping to about the latitude of Cabo de Santa Caterina (2 degrees N.), the approximate limit of navigation with favourable currents on the outward voyage. Though his monopoly lasted only six years, on the face of it his explorations represented an astonishing rate of increase over the tentative efforts of Dom Henrique. But conditions were now more propitious. A way had been found through some of the most adverse of the sailing conditions that made the routes to and from Africa so arduous, and a route home, difficult but practicable, had been established via well-stocked ports. Moreover, the profitability of the enterprise had been enhanced by the discovery of further saleable products in the form of ivory and malaguetta ‘pepper’.
The crown rescinded Fernao’s monopoly in 1475, perhaps in order to confront Castilian interlopers on the Guinea coast. The navigation of west Africa now became the responsibility of the senior prince of the royal house, the Infante Dom Joao. Henceforth Portugal had an heir and, from his accession in 1481, a king committed to the further exploration and exploitation of Africa. He had a militant and organising mentality, forged in war against the Castilian corsairs. As ‘Lord of Guinea’ he boosted the prestige of African enterprise at home, centralised the control of commerce, built an emporium for the gold trade about 100 kilometres from the mouth of the river Volta and presided over an extraordinary turnover in baptisms and rebaptisms of rapidly apostasising African chiefs. He was also the patron of heroic new feats of exploration, which dwarfed those of the eras of Dom Henrique and Fernao Gomes.
The voyages of Diogo Cao, who made contact with the kingdom of Kongo in 1482 and, having entered the river Zaire, established the shape of the coast to just beyond 22 degrees S. in 1485, were made with amazing tenacity in the face of adverse winds and currents. In the summer of 1487, Cao was followed by Bartolomeu Dias, who left Lisbon with three ships and a commission to find the ocean route round Africa. At first retracing Cao’s coastbound route, he seems subsequently, with great daring, to have turned away from the coast, perhaps in about 27 or 28 degrees S., in search of a favourable wind. The result was a major contribution to knowledge of the wind-system of the south Atlantic, for Cao encountered westerlies which carried him to a landfall some 300 miles east of the Cape of Good Hope. The expedition seems to have been exceptionally well provisioned, suggesting that the detour into the open ocean was planned in advance.
The discovery of new sources of gold and slaves meant that the direct economic effects of west African exploration were potentially revolutionary. Yet in the sixteenth century the development of transatlantic and Indian Ocean trade largely left behind the west African world of dangerous shores, inhospitable climes, difficult access and relatively limited rewards. Exploration had, however, yielded great benefits for the growth of Latin Christendom’s world-picture. The discovery of the south Atlantic wind-system was the key which unlocked access to the Indian and Pacific Oceans. The shape and southward reach of Africa had been established by empirical evidence after a long period of insufficiently informed debate. The African enterprise had, moreover, taken European seamen beyond the equator for the first time to a hemisphere where, out of sight of the Pole Star, an unfamiliar heaven made new demands of celestial navigators: this proved an enormous source of stimulation to the science and technology, as well as the prestige, of navigation. The early modern revolution in the methods, range and results of navigation was thus prepared and, to some extent, pre-figured, in the fifteenth-century African voyages.