Neither the intent nor the achievement of Magellan's voyage was to demonstrate that the earth was a globe; that had been common knowledge, to the educated, for centuries. The picturesque names of Cosmas Indicopleusthes, ‘the Indian Traveller’, and of his book Christian Topography (c. 540), are all too easily adaptable as light relief in elementary textbooks; so is his extraordinary model of the world, just like an old-fashioned trunk with rounded lid and inner tray corresponding to the Firmament. This engaging irrelevancy is perhaps in part responsible for the vulgar error that, until Columbus and Magellan, only a very few unorthodox persons did not believe in a flat earth; an error persisting to our own day.^[13] While Cosmas himself had very little influence, and ‘the passionate declamations of a Lactantius or a Cosmas are only individual opinions’ and did not commit the Church,^[14] it is also true that most of the early Fathers repudiated sphericity, with more or less conviction; but some, and those of the greatest, seem doubtful—Clement, Origen, Augustine—or, like St Ambrose and St Basil, simply regard the question as irrelevant to a Christian's beliefs.

But obscurantism was perhaps never total, and did not endure. Already the Venerable Bede (673–735) seems to have inclined to believe in a globe. While one cannot always be sure that a medieval writer who refers to a ‘round’ earth is thinking of a disc or a sphere, yet in general ‘By the eighth century the Church appears to have largely forgotten its early doubts about the shape of the earth and- 5 -to have accepted the saner opinions of [most of] the Ancients’,^[15] and seventy years ago Beazley wrote

Unfortunately, although in the twelfth century William of Conches could return Cosmas's hysterical attacks on believers in the sphere by asserting that flat-earthers were ‘bestial’,^[17] it still seems necessary to repeat it.

In the Middle, as distinct from the ‘Dark’, Ages the real debate was on the question, theologically much more serious, of the Antipodes: whether there were lands on the other side of the globe, whether they were accessible, whether anyone could live there. Although, as is usual with the Holy Writ of any belief, texts could be taken in differing ways, there was nothing in Scripture incompatible with a spherical earth. ‘The world also is stablished, that it cannot be moved’, God ‘hangeth the earth upon nothing’—both texts would fit neatly into the Ptolemaic scheme of spheres; and God ‘sitteth upon the circle of the earth.’ But—Adam was the father of all men, the Apostles were commanded ‘Go ye into the world, and preach the gospel to every creature’;^[18] and how could that be if, as had been generally held from antiquity,^[19] the Antipodean lands, if indeed they existed, were barred from the Oecumene, the known habitable world, by a zone so torrid that in it human life was impossible? And hence the Antichthones or Antipodeans themselves, if they existed, how could they be sons of Adam?

The struggle over the Antipodes was longer and sterner than that over the Globe; nevertheless by the twelfth century the concept of antipodal lands seems to have been very generally accepted; one powerful line of argument saw an Austral land-mass as necessary to preserve the balance of the globe. Some thought that such lands were habitable, a few that they were inhabited—perhaps (but this was indeed dangerous thinking) by an entirely different race of men, not of the seed of Adam. For one thing, the reports of Marco Polo and of the Arabs who had travelled far to the south in Africa seriously eroded the northern frontiers of the supposedly uninhabitable zone; for another, men of the weight and standing of Albertus Magnus and Roger Bacon argued the question acutely and came down firmly in favour of habitable lands beyond that zone.^[20]

No doubt for centuries the mass of the illiterate populace, if they thought at all about such things, were content to live out their laborious lives under the dome of heaven and on an undefined middle-earth; but global thinking was not confined to academic speculation and treatises in Latin. The travels of that genial impostor ‘Sir John Mandeville’, written about the 1350s, became the most popular science fiction of the Middle Ages, the top best-seller; but, like modern writers in the genre, Sir John had provided himself with an extensive if uncritical scientific background. Mandeville, whoever he was, gathered his materials from any and every available source, but these included solid works- 6 -such as the De Sphaera (c. 1220) of John of Holywood or Sacrobosco, a standard manual for at least 300 years. The chapter of the Travels on the evil customs of the Isle of Lamory (Sumatra) deals concisely with nudity, community of women, and cannibalism, and then plunges into a demonstration not only that ‘the earth and the sea be of round form and shape’ but also that there existed habitable, and inhabited, Antipodes:

And this was written in a book which became ‘a household word in eleven languages and for five centuries’, surviving in some 300 MSS.^[21]

Nevertheless, dread, especially popular dread, of the torrid zone long persisted, and had to be reckoned with. To antiquity, the obstacles were searing heat, deserts, vast mountains, though on some versions of the world there was an equatorial sea. In the Middle Ages the seas themselves, beyond known limits, came to be considered evil, the home of unspeakable horror—

Such terrors applied especially to the seas which were most relevant to any hope of a waterway to the Indies around Africa. The prime source for these tales of mystery and terrified imagination seems to be Arabic: from the tenth to the fourteenth centuries writers of the stature of Masudi, Idrisi, and Ibn Khaldun had spoken of the Western Ocean as a ‘Green Sea of Darkness’, viscous and yet storm-swept, shrouded in thick and perpetual gloom; and ships might be dragged down to the hideous deep by some many-tentacled monster, or even (perhaps) by the giant hand of Satan himself.^[23] Practice rather than theory dispelled this myth; nevertheless for fifteen years, 1419–34, the bastion of Cape Bojador, the ‘bulger’, girt by treacherous shoals, reefs, and currents, marked a ne plus ultra to the Portuguese thrusts to the South.^[24]

Ptolemy is conventionally known as the Geographer, but this was not his role until very late in the Middle Ages: for most of these centuries he is the great cosmologist of the Almagest, with its complex system of epicycles to account for the movements of the heavenly bodies. His geographical work was known to the Arabs, but had singularly little impact in the Christian world.^[25] But a Latin version of his Geographia, direct from the Greek, was made in Italy about 1406, and there are over forty MSS. still extant in one or the other language; the work was printed in 1475.^[26] The special feature of Ptolemy's work, excellent in theory,- 7 -was his introduction of a system of co-ordinates for some 8000 places throughout the then-known world; given the lack of instrumental techniques, the longitudes in particular could not be anything but exceedingly rough approximations, often grossly incorrect even in the Mediterranean. But they gave a spurious air of precision, and from them maps could be constructed, or reconstructed (Figure Plate I, “THE PTOLEMAIC WORLD MAP. ”).^[27] These maps had a strong influence on geographical thinking in the fifteenth century, and, for the Spanish under Columban influence, even later.^[28]

By a most happy scientific error, perhaps the most fruitful in all history, Ptolemy rejected the remarkably good estimate for the circumference of the globe made by Eratosthenes nearly 400 years before him, and accepted a value about one-sixth too small.^[29] He compounded this error by inflating the longitudinal extent of the Oecumene, from the Fortunate Isles (the Canaries) to the land of the Seres or China, making it no less than 180°, half the world's round, instead of a true distance of about 140°—and moreover he set no eastern limit to China, so that the land of Eurasia might stretch out eastwards indefinitely. He thus reduced the globe by about one-sixth and then stretched Eurasia, in the relevant latitudes, over one-half (or more) of this reduced extent, instead of two-fifths. Columbus, as we shall see, improved even upon this; he had other authorities, but without that of Ptolemy—as it were his minimal case—it is unlikely that he would have got the backing for his voyage.

- 8 -

The idea that Asia might be reached by sailing westwards from Europe has a long and respectable pedigree; indeed, the very first hint is in Eratosthenes himself.^[30] But his work survived only in fragments quoted by other writers, and he had no influence in the Middle Ages, except that through Macrobius (c. 395–423) his value for the size of the globe was widely accepted; but Roger Bacon, for instance, followed Ptolemy in thinking that the distance between Spain and ‘the beginning of India’ was quite small.^[31] More important was the virtual rediscovery of the Geographia after 1406, in fact one of the most important episodes in intellectual history.

Pierre d'Ailly, Cardinal of Cambrai, had produced about 1410 the Imago Mundi, a careful conspectus of the academic geography of his time. By 1414 he had seen a Latin version of Ptolemy's Geographia and hastened to exploit this new source in further geographical works, which formed an important part of Columbus's documentation. Ptolemy had cited, though he did not accept, the view of his predecessor, Marinus of Tyre, that the extent of the habitable world was at least 225° of longitude; and again Marinus set no limit to the eastwards extension of Eurasia.^[32] Columbus seized upon this extension—nearly two-thirds instead of one-half—and by adjusting every variable or uncertainty to his own desires he managed to reckon the distance from the Canaries to Cipangu (Japan) as a trifle of 4445 km, well under a quarter of the true distance. Marinus brought China as far east as Hawaii; Columbus brought Japan to the Virgin Islands!^[33]

The total effect of the geographical speculations of the fifteenth century was, then, to envisage a globe much more manageable, in dimensions at least, than it was in reality.

Another aspect of the Ptolemaic scheme, however, was much less convenient. This was the view that the southern coasts of Asia curved round in a vast arc to join Africa, making of the Indian Ocean an enclosed sea. To accept this was indeed to make a retrograde step, but fortunately its significance was much greater in academic circles than in the world of affairs.

The geographical compilers of the later Middle Ages by and large ignored the first-hand travel reports which could have been available to them. Mandeville, a ‘popular writer’, of course raided everybody, but although there were exceptions (such as Bacon's mention of William of Rubruck's mission to the Great Khan), scholars usually preferred the endless rehashing of classical authority, mixed with material from the vast and confused compilations of the Dark Ages. By critical examination of conflicting classical views the greater writers did indeed attain to some originality, but this was more in the direction of cosmographical speculation—the Antipodes, the Oecumene—than in topographical geography. Marco Polo was not as universally derided or ignored as tradition suggests—the number of manuscripts, no fewer than 119, attests this. By the fifteenth century, however, he was being taken more seriously, especially perhaps his exaggerated view of the wealth of Cipangu, which he had not seen. His book was studied not- 9 -only by Columbus but by Prince Henry; a manuscript of it was presented to the latter's brother Dom Pedro by the Doge of Venice.^[34] Nevertheless the general cast of academic geography was excessively bookish.

But alongside the clerisy, though outside business dealings not much in touch with it, was the merchantry. Ptolemy, as J. H. Parry remarks, was both stimulating and enslaving—

But much earlier such men, perhaps less regularly commissioned, had pioneered new trade routes or reopened old ones: Polo himself is witness, and his successor Pegolotti, who advises the overland trader into central Asia to pick up a Crimean woman as cook and concubine: there is no obligation, but life will be easier that way.^[36] ‘Now it is this more humble kind of people whom we must consider as the principal mediators and teachers’ between Islam and Christendom;^[37] as well as concubines, such hard-headed and professionally observant characters undoubtedly picked up also a vast amount of firm geographical knowledge from their peers, of all races and creeds, in the ports and caravanserais from the Crimea to the Nile. This would have included the knowledge that the African coast ran south far beyond the remotest Ptolemaic cape.

The Arab cartographic tradition seems always to have shown Africa as encircled by sea on the south, and this tradition is carried on by the Sanuto world-map, between 1306 and 1321; but these are ‘disc-maps’, reminiscent of the ‘T–O’ type common in the earliest Middle Age, and of limited value as evidence of real knowledge. Really extraordinary is the Laurentian Portolano of 1351–70, as Beazley says ‘among the confounding things of history’—if we could accept it as all of a piece, which is impossible. This shows an outline for the whole African continent which is astonishingly real, and yet no known or even legendary voyage—at any rate since the Phoenician one from east to west, reported by Herodotus—could have accounted for it; but most likely everything south of Cape Non, or at best Sierra Leone, is a later addition under Portuguese influence.^[38] We may also recall the Vivaldi brothers, who sailed from Genoa in 1291 to seek the trade of the Indies by sea. They were probably not the first to venture down the Mauretanian coast, never to return.

By 1457–9 the Genoese World-Map and Fra Mauro show Africa as a peninsula, and the Indian Ocean as an open not an enclosed sea; and half a century before the Ptolemaic map was in print, Prince Henry's men were disregarding the Ptolemaic view of Africa as curving round to join India.^[39] The complex claims to priority of Castilians, French, Genoese, Portuguese, and even (and perhaps) one English couple,^[40] in the eastern Atlantic islands and on the opposite African coasts do not- 10 -concern us here. What is significant is the Portuguese drive down the west coast, beginning soon after the capture of Ceuta from the Moors in 1415 and, though occasionally interrupted by other political concerns, maintained with remarkable steadiness until complete success was achieved at the end of the century. This involved the acquisition of accurate knowledge of winds, currents, and sailing courses, especially the voltas or return routes, which were well off-shore: Vasco da Gama's great westwards sweep on his way to the Cape was perhaps less daring but better-prepared than is generally allowed. This drive of course was the great enterprise of the Infante Dom Henrique—the title of ‘the Navigator’ is a spurious piece of British romanticism. It is an exaggeration to institutionalise the group that Henry gathered round him into a formal ‘Academy of Sagres’; but it was remarkable in that it included some of the best informed cosmographers and most practical seamen of the age; some of its scholars were Jews in close touch with the Arab tradition. Motives were doubtless highly mixed—the Crusade against the Moors, the geostrategic advantage of holding Moroccan fortresses, the propagation of the Faith, gold, slaves, adventure, fame, intellectual curiosity. ‘Guinea gold’, slaves, ivory, and the inferior ‘malagueta’ pepper of West Africa had long been available in Mediterranean ports from Muslim traders—at a price; and the desire to cut out these middlemen was certainly a factor. It would be difficult to say just when the trade, especially the spice trade, of the Indies became a dominant, but the Papal Bull Pontifex Romanus of January 1454 definitely speaks of Henry's intention to circumnavigate Africa, though in a context of struggle with the infidel rather than of trade. Nevertheless, while D. Henrique ‘certainly was always imbued with religious fervour … after the earlier years of his career he was, above all, the administrator of an economic enterprise of national importance and international consequence.’^[41]

Alfonso X, the Wise, King of Castile from 1252 to 1284, a notable patron and indeed practitioner of learning, sponsored the revision of the Ptolemaic astronomical tables, and is reputed to have exclaimed that if he had been consulted at the Creation, he would have planned a simpler and tidier Universe.^[42] It is perhaps fitting that the definite breach of Ptolemy's barrier between Europe and the Indies should have been made by Castile's rival Portugal just over a century after Aljubarrota, the ‘Bannockburn’ which broke the Castilian hold over the smaller kingdom. In 1488 Bartolomeu Dias sailed far beyond Cabo Tormentoso, his Cape of Storms, renamed by the King Dom João II the Cabo da Boa Esperança.^[43] The way to the Indies lay open.