Reading passage
Long before satellites photographed the earth from orbit, human beings were drawing maps. The oldest surviving candidates, scratched onto cave walls and mammoth tusks more than twenty thousand years ago, may depict hunting grounds or star patterns, though their interpretation remains disputed. What is clear is that mapmaking is older than writing: the impulse to fix spatial knowledge in a durable image appears to be among the most ancient expressions of abstract thought, and every civilisation that left records seems independently to have produced maps of some kind.
The earliest unambiguous maps come from Mesopotamia. Clay tablets from Babylonia, dating to around 2300 BCE, show plots of land with measurements, drawn for purposes of taxation and inheritance. Far more ambitious is the Babylonian World Map of roughly 600 BCE, a palm-sized tablet that depicts the earth as a flat disc encircled by a bitter river, with Babylon near the centre and distant regions labelled as places where, in the accompanying text, mythical creatures dwell. The tablet is less a navigation tool than a statement of cosmology: geography, myth, and political centrality are fused into a single image of a world ordered around its makers.
Greek thinkers transformed mapping from cosmology into geometry. Anaximander of Miletus, in the sixth century BCE, is credited with the first Greek world map, and by the fourth century Aristotle was arguing, on observational grounds, that the earth was a sphere. The decisive figure was Eratosthenes, head of the great library at Alexandria around 240 BCE. By comparing the shadow cast by a stick at Alexandria with the absence of shadow at Syene, modern Aswan, on the same day, he calculated the earth's circumference as some 250,000 stades. Depending on which stade length he used, his figure lies within roughly two to sixteen percent of the true value, an astonishing achievement for a measurement made with a stick and a camel caravan's pace count.
The climax of ancient cartography was the Geography of Claudius Ptolemy, compiled in Alexandria around 150 CE. Ptolemy assembled the coordinates of some eight thousand localities, explained how to project a spherical earth onto a flat sheet, and provided instructions from which an entire world map could be reconstructed. His work contained serious errors: he underestimated the earth's size, overestimated Asia's eastward extent, and depicted the Indian Ocean as an enclosed sea. Yet its mathematical framework was so authoritative that when the text was rediscovered in Byzantium and translated into Latin around 1406, it shaped European geography for two centuries. Columbus sailed west in 1492 partly because Ptolemy's small earth and long Asia made the ocean crossing to the Indies seem shorter than it truly was.
China developed its own cartographic tradition independently and, in some respects, more precisely. Maps drawn on silk, excavated from a tomb sealed in 168 BCE at Mawangdui, depict the topography of southern China with remarkable accuracy, using symbols for mountains, rivers, and roads. The third-century official Pei Xiu is credited with formulating six principles of mapmaking, including the use of a rectangular grid, scale, and the correction of distances for terrain, principles comparable to those Ptolemy articulated a century earlier. Unlike the Greek tradition, which was largely lost to Europe for a millennium, Chinese cartography developed continuously, feeding into the great printed maps of the Song dynasty.
Medieval Islamic scholars became the custodians and critics of the classical inheritance. Caliph al-Mamun sponsored a ninth-century world map in Baghdad and a fresh measurement of the earth's circumference, while al-Idrisi, working at the court of the Norman king Roger II of Sicily around 1154, produced a silver planisphere and a book of geography whose maps remained the most accurate available for three hundred years. Conventionally, al-Idrisi's maps place south at the top, a reminder that orientation is a cultural choice rather than a technical necessity.
In Christian Europe, by contrast, the most celebrated medieval maps served devotional rather than navigational purposes. The Hereford Mappa Mundi, drawn around 1300 on a single sheet of calf skin, places Jerusalem at the centre and Paradise at the top, arranging the known world as a stage for sacred history. Accuracy of coastline was beside the point; the map was an encyclopedia in graphic form, compressing time and space into a sermon. Yet the same period produced the portolan charts of the Mediterranean, drawn from sailors' compass bearings and dead reckoning, whose coastlines are startlingly accurate and whose origins remain one of the unresolved puzzles of cartographic history.
The ancient and medieval mapmakers left a double legacy. They demonstrated that the earth could be measured, gridded, and projected, supplying the mathematical skeleton on which the age of exploration would hang its discoveries. But they also revealed how maps encode the worldview of their makers: Babylon at the centre of the Babylonian world, Jerusalem at the centre of the Christian one, and south at the top in the Islamic tradition. The modern atlas, for all its satellites and surveying instruments, inherits this lesson. Every map selects, simplifies, and centres, and the history of cartography is in part the history of who held the power to decide what mattered.