Where is Paradise? For 1,000 years, Europeans believed it could be found, and their speculations were fed by the voyage of Saint Brendan, a 6th-century Irish monk who sailed westward on the instructions of an angel who came to him in a dream. In their five years at sea, he and his crew claimed to have encountered the devil in his palace, an island belching fire, a floating crystal temple, and finally Paradise, as a beautiful island.

For the next 1,000 years, this island regularly appeared on maps, set in varying parts of the Atlantic: sometimes among the Canaries, sometimes near Cape Verde, sometimes off the coast of Newfoundland. The 7th-century archbishop Isidore of Seville claimed to know both where it was and exactly what it was like; seven centuries later the English traveller Sir John Mandeville wrote a detailed description from hearsay, while admitting that he personally had not yet been there.

We may laugh at the way this fantasy was routinely enshrined in maps purporting to be reflections of factual reality, but throughout history maps have often served purposes which are political, religious or philosophical, rather than scientific. People created maps not just to convey a sense of physical place - here in relation to there - but to situate themselves in the world, and in relation to the powers that governed it: when God was believed to rule, his kingdom had to figure too.

And if the Earth was believed to be a flat plate supported by four elephants standing on the back of a turtle, or if it was thought to be surrounded by an ocean with the vault of the sky resting on the Earth’s rim, as Homer assumed, then those images also became part of the map.

But the very first mapmakers had more limited, practical aims; they did not aspire to encompass the world. Marshall Islanders in the Pacific lashed sticks together with fibres to depict winds and wave patterns in a three-dimensional chart model, and inserted shells to denote islands; early Mexicans indicated roads by lines of footprints; Eskimos carved coastal maps in ivory, and early Europeans drew sketch maps on the walls of their caves.

Chinese cartographers, ahead of everybody else, had mapped their whole kingdom by 1125 bc, but their knowledge of the wider world was almost non-existent: they believed it was square, and they assumed their country formed the bulk of it. When Indian Taoist doctrine filtered through in the 4th century bc, announcing that China only occupied one eightieth of the Earth’s surface, Chinese maps changed accordingly.

In the 6th century bc, Babylonians, whose clay town-maps look businesslike even today, made the earliest recorded attempt at a reasoned conception of the universe. They divided the sky into 360 degrees, and the day into hours, minutes, and seconds, thus allowing time to be plotted in relation to the stars. The ancient Greeks brought logical analysis to bear on the Babylonians’ astronomical observations, and it was this which led to Pythagoras’s conclusion, in the 6th century bc, that the Earth was a sphere rather than flat.

Three centuries later, Eratosthenes, head of the great library of Alexandria - the nearest thing in the ancient world to a modern science research centre - devised a way of measuring the size of the Earth using nothing more complex than the rays of the Sun, a well, and a vertical stone column. His calculation may have been 16 per cent out, and he knew nothing about the lands and seas covering what he had measured, but this was still a remarkable achievement.

A century and a half later, in the 2nd century ad, Eratosthenes’s great Alexandrian successor, Claudius Ptolemy, introduced the cartographic system that we use today, with his idea of latitude and longitude, and his insistence on the use of astronomical observation to calculate geographical location. But for Ptolemy the known world was much smaller than it is in reality; it consisted of just three continents - Europe, Asia, and Africa - with a relatively short stretch of water separating Europe and Asia; it was the persistence of this assumption that encouraged Columbus to sail westward, 1,500 years later, in the confident expectation that he would make landfall in Asia, rather than in an America of which Ptolemy and his disciples had not dreamt.

If the Alexandrian research tradition had continued after Ptolemy, such misconceptions would probably have been eliminated, but a long period of civil strife supervened: when a Christian mob destroyed the library and its contents in ad391, Ptolemy’s ideas for scientific cartography became lost to the Western world for the next 1,000 years, and faith triumphed over reason.

Ptolemy’s Western successors rejected scientific enquiry as pagan and irrelevant: locating Paradise was considered to be much more important than giving the latitude of a city. The first of these “scholars” was a Roman named Gaius Julius Solinus, whose popular book of travellers’ tales left its mark on almost every medieval map.

In the East, he said, there lived hoofed men whose ears had such long flaps they acted as clothing; in Germany, you could find birds whose feathers gave light in the dark; in Africa, hyenas cast shadows which could rob dogs of their bark, while the ants by the Niger were as big as mastiffs.

A much-travelled Christian monk named Cosmas compounded the mischief by scorning the idea that the Earth is a sphere, and claiming that its true shape could be found in the Holy Scriptures, which referred to the “four corners” of the earth; it was, he asserted, a flat parallelogram. (Such nonsense did not die with the Renaissance: in the late 19th century, the American Koreshanity sect was claiming that we live on the inside surface of a hollow earth.) Even more mischief was extracted from the Bible, aided and abetted in this respect by the Qur’an, in the form of those mythical giants, Gog and Magog, who were believed to be threatening mankind with destruction, and against whom ramparts were built; a 14th-century Arab geographer produced a map in which he renamed the Great Wall of China as the “Wall of Gog and Magog”.

Some medieval maps were stylised reflections of journeys, some outlined the route to heaven, and some were designed to glorify popes and princes.

But the most common form was circular, reflecting “the circle of the earth”

(Isaiah 40:22), and this became known as the T-O map. Here, the Earth was surrounded by an ocean - the O - within which lay the three known continents, separated by waters drawn with diagrammatic neatness in the shape of a T.

Since nearly all medieval maps had East at the top, Asia filled the upper half, separated from Africa and Europe by the Nile and the Don; the Mediterranean formed the upright of the T. This way, Jerusalem could conveniently sit at the centre of the map, thus satisfying the demands of the church. Moreover, this T-O form was used by Arab cartographers, too, and it’s not dissimilar to the “sacred geography” maps of the Jain sect in India (though their maps were infinitely more complex). This form must reflect a universal human impulse.

The only practical, as opposed to ideological, maps during the Middle Ages were road maps and sailing charts: scientific map-making was only revived thanks to the Renaissance urge to discover. Ptolemy’s Geography was one of the classical texts printed when movable type was first invented, and map-makers took note, even if his Mediterranean was too long, and his Ceylon was bigger than his India. By 1500, all educated Europeans assumed once more that the Earth was a sphere. But Columbus actually got his global dimensions much further wrong than Ptolemy’s, and his failure to understand the theory of Eratosthenes led him into even greater error: his discovery of America in 1492 was entirely accidental. Ferdinand Magellan’s voyage, in 1519, by which he proved that the Earth was round, was a much greater achievement.

And when, in 1569, the Dutch cartographer Gerardus Mercator devised a way of translating the sphere with relative accuracy into the flatness of a map, map-making really took off. But Mercator’s famous “projection” - on which navigation (together with many atlases) is still based - has a built-in distortion which gets worse the farther you move away from the Equator: it suggests that Greenland is the same size as Africa, rather than the true representation which would be one-fourteenth the size. This distortion inspired the German cartographer Arno Peters to publicise an “equal area” projection in 1974, which more truthfully reflected reality: aid agencies now use Peters in preference to Mercator. However, Mercator’s work was still the breakthrough: modern cartography was born, and his Dutch compatriots proceeded to lead the way in the creation of ever more impressive atlases, at the apex of which process stood the sumptuous Atlas Maior by Joan Blaeu.

When it was published in 1665, this book was the most expensive money could buy: published in 12 massive volumes, first in Latin and then translated into Dutch, English, German, French, and Spanish, it was the cartological masterpiece of its day. It opens with a ringing declaration of the importance of maps: “For no exploit great or small is performed without location, nor can any place on earth be accurately defined without Geography... The general must know where he may lead his army, where encampment is best, where ambushes can be laid and where carefully avoided... How, without knowledge of geography, can we bring back over land and sea from far-off countries whatever is lacking in our own?” Enlisting the help of maps, Blaeu continues, “we may set eyes on far-off places without so much as leaving home: we traverse impassable ranges, cross rivers and seas in safety; by the power of the imagination we swiftly journey East-West and North-South at a single glance.”

Blaeu gratefully acknowledged his debt to the great geographers of the past, from Ptolemy to Mercator, and, like the editors of Lonely Planet guides today, invited his readers to send in any corrections or new information they had so that future editions might be even more definitive.

Further reading

* The Map Book, edited by Peter Barber, Weidenfeld and Nicolson pound;25

* The Mapmakers, by John Noble Wilford, Pimlico Press pound;12.50. The illustrations above and right are taken from this book

* An illustrated description and explanation of the Marshall Islanders’

stick charts can be found at www.janesoceania.commicronesian_stick_chart