History of World Maps — 2-part series

• Part 1: Mapping the World’s Contours (this article)
• Part 2: The Lies of Flat Maps

History of World Maps, Part 1: Mapping the World’s Contours

In September 1522, a ship limped into the harbor at Seville, Spain, carrying just eighteen men. Three years earlier, five ships and 270 crew had set out. The rest — more than 250 of them — had died of scurvy and starvation, been swallowed by storms, or perished on foreign shores. The captain, Ferdinand Magellan, had already been killed in battle on the Philippine island of Mactan. Yet this bloody homecoming proved something entirely new to humanity: the world was a connected sphere, and if you kept sailing west, you would eventually arrive back where you started.

It had taken thousands of years to confirm that truth. And the journey to get there was anything but quiet.

The World’s First Map: When Babylon Stood at the Center of Everything

Sometime around the sixth century BCE, a scribe living near Sippar in present-day Iraq etched cuneiform script and drawings onto a clay tablet no larger than a human palm. Measuring roughly twelve centimeters across, this tablet is the oldest known world map.^[1] Scholars call it the Imago Mundi — “Image of the World” — and it now resides in the British Museum.

The map shows the Euphrates River running top to bottom, with Babylon and its surrounding cities marked along its banks. The entire known world sits encircled by a ring of sea called the “Bitter River,” and beyond that ring, eight triangular regions indicate lands still unknown — the realm of legend.^[1]

What matters about this map is not its inaccuracies. What matters is what it reveals about how people understood their world at the time. Babylon always sat at the center. The world consisted of known lands, a surrounding sea, and an unknowable beyond. This structure repeats itself — remarkably — in civilizations on the opposite side of the globe, across thousands of years.

The Greek Question: Can a Map Be Calculated?

Where the Babylonians drew the world by belief, the ancient Greeks tried to measure it by reason. In the sixth century BCE, Anaximander of Miletus is credited as the first person to attempt a map of the entire earth as a single surface.^[2] His map has not survived, but descriptions by later geographers Strabo and Agathemerus suggest it placed Europe, Asia, and Africa (Libya) in a circular arrangement around the Mediterranean.

Around 150 years later, Hecataeus refined Anaximander’s work.^[2] But the decisive leap came in the third century BCE with Eratosthenes. He noticed that at the summer solstice, the sun shone directly to the bottom of a well in Syene (modern Aswan, Egypt) at noon, while at the same moment in Alexandria it struck the ground at a slight angle. Using the difference in that angle and the known distance between the two cities, he calculated the circumference of the earth.^[3] His result — roughly 40,000 km — is remarkably close to the modern figure of 40,075 km. The conviction that the earth was a sphere, and that it could be described mathematically, began to take root.

The culmination of this tradition was the Geographia of Claudius Ptolemy, writing in Alexandria in the second century CE.^[4] Spread across eight volumes, the work assigned latitudes and longitudes to more than 8,000 place names known at the time. Latitude was measured from the equator; longitude from the Canary Islands (the “Fortunate Isles”), then believed to be the westernmost point of the world. Introducing a coordinate grid to maps, and seriously grappling with how to project a spherical earth onto a flat surface — these were Ptolemy’s real contributions.^[4]

But the work contained a fatal flaw. Ptolemy calculated Asia as far wider east-to-west than it actually is, depicted the Indian Ocean as an enclosed sea, and drew Africa curving eastward to connect with Asia. These errors distorted Western geography for more than a thousand years. When Christopher Columbus set sail westward in 1492, one of his reasons for believing he could reach Asia that way was Ptolemy’s overestimate of Asia’s breadth.^[4]

The Medieval Divergence: Maps That Drew Faith, Not Fact

Ptolemy’s Geographia vanished from Western Europe. More precisely, it was forgotten. After the fall of the Western Roman Empire in 476 CE, as intellectual life contracted, European mapmaking took a radically different turn.

The defining world maps of medieval Europe were known as mappae mundi. Among them, the T-O map divided a circular world with a T-shaped body of water: the upper half was Asia, the lower left was Europe, the lower right Africa.^[5] At the very top of the map — to the east — sat the Garden of Eden. And at the center, always, was Jerusalem.

The most celebrated example is the Hereford Mappa Mundi, created around 1300. On a sheet of vellum measuring 1.6 meters tall and 1.3 meters wide, it packs hundreds of cities and biblical sites.^[5] Geographic accuracy was never its purpose. It was a theological instrument — an attempt to contain the whole of history, from Creation to the Last Judgment, on a single surface.

It would be too easy to dismiss this as a bad map. The question these maps were trying to answer was simply different. Not “where should I go?” but “where do we stand within God’s creation?”

Islamic Cartography: The Most Accurate Map, Drawn with South at the Top

Meanwhile, across the Islamic world, something very different was taking shape. Arab scholars translated and preserved Ptolemy’s writings while gathering accounts from countless travelers and merchants to accumulate an extensive store of geographic knowledge.

The greatest product of this tradition came from Muhammad al-Idrisi, who worked at the Norman court of King Roger II of Sicily in the twelfth century. Over sixteen years, beginning in 1138, he compiled Kitāb Rujār (the “Book of Roger”), also known as the Tabula Rogeriana — a work comprising seventy detailed maps and extensive geographic description.^[6] Al-Idrisi also engraved a world map onto a silver disc weighing some 300 pounds (roughly 136 kg).

The map’s most striking feature is its orientation. In Islamic cartographic tradition, it was common to place south at the top — this brought Mecca and the Arabian Peninsula to the upper portion of the map, the position that carries the greatest visual prominence.^[6] Recognized as the most accurate world map of its era for centuries, al-Idrisi’s work is said to have been consulted by Vasco da Gama when he later charted a sea route to India.

The sharp contrast between medieval European and Islamic maps of the same period illustrates something fundamental: maps were never simply containers for geographic data. They were containers for a civilization’s worldview. Deciding what to place at the center was not a geographic choice — it was a civilizational one.

Compasses and Portolan Charts: Maps Made by Sailors

As the Middle Ages gave way to their later period, a new force entered mapmaking: merchants and sailors crossing the sea. For them, a map was not a theological document. It was practical information on which lives depended.

The portolan chart, used for Mediterranean navigation from the late thirteenth century onward, was born from exactly this need.^[7] These charts rendered coastlines with striking precision, filled with the names of hundreds of harbors and a dense web of rhumb lines indicating compass bearings. A sailor would locate his departure and destination ports, draw a line between them, and read off the bearing needed to follow it.^[7]

Critical to the portolan chart’s rise was the spread of the compass. Magnetic compass technology had reached Europe through Islamic traders around the twelfth century,^[8] making it possible to hold a course even when clouds hid the stars. Mediterranean navigation became dramatically more precise as a result. The accuracy with which portolan charts reproduced the coastlines of the Mediterranean and Black Sea owed everything to the accumulated navigational data the compass made possible.^[7]

Yet portolan charts had a fundamental limitation. They were flat projections that ignored the curvature of the earth, which made them useless for crossing wide open oceans like the Atlantic.^[7] To venture beyond the Mediterranean into the unknown seas, a wholly different kind of knowledge was required.

The Age of Exploration: Voyagers Who Redrew the Map

In the late fifteenth century, Portuguese and Spanish explorers plunged into the Atlantic. What they found was not just new land. The world map itself began to be redrawn from scratch.

In 1492, Christopher Columbus, convinced that sailing west would bring him to Asia, reached the islands of the Caribbean.^[9] He died believing he had touched Asia. In 1498, Vasco da Gama rounded the Cape of Good Hope at Africa’s southern tip and reached India.^[9] His voyage proved what Ptolemy’s map had denied: the Indian Ocean was not an enclosed sea but one connected to the Atlantic. The line on the map joining Africa to Asia was quietly erased.

But the fact that the world was truly one connected sphere was proved in flesh and blood by the Magellan-Elcano expedition.

From 270 to 18: What Magellan Proved

On September 20, 1519, Ferdinand Magellan set sail from Sanlúcar de Barrameda, Spain, with five ships and a crew of 270. The mission was to reach the Spice Islands (the Maluku Islands) in the name of Spain — by sailing west, and only west.

The voyage was an ordeal from the start. Months passed just searching for a passage through South America to the Pacific. Transit through what we now call the Strait of Magellan took 38 days; crossing the Pacific took more than 99.^[10] As water and food ran out, sailors ate rats and chewed leather. Scurvy swept through the fleet. Magellan himself was killed on April 27, 1521, fighting the forces of local chieftain Lapu-Lapu on the Philippine island of Mactan.^[10]

Command changed hands several times. In the end, Juan Sebastián Elcano brought the last surviving vessel, the Victoria, into Seville on September 8, 1522.^[10] Of the 270 who had sailed out, only 18 returned with the ship.

What this homecoming proved was not merely a new trade route. It proved that the earth is genuinely round — that you can set out along its surface in any direction and return to where you started. This was not an abstract theorem. It was a truth paid for in lives.

Why the Maps Were Still Incomplete: The Problem of Longitude

Even as the explorers of the Age of Exploration pushed the edges of the known world outward, the maps they produced carried a crippling weakness: no one could determine their exact position.

Latitude was manageable. By measuring the height of a star — particularly the Pole Star — above the horizon, a navigator could calculate how far north or south of the equator they were.^[11] Longitude — position east or west — was a different matter entirely. Finding your longitude required knowing the time difference between your current location and a fixed reference point (such as your home port). Since the earth rotates 360 degrees in 24 hours, a one-hour time difference equals 15 degrees of longitude.^[11]

The problem was that no timepiece of the era could keep accurate time at sea. The rolling of a ship and constant changes in temperature and humidity played havoc with mechanical clocks of the day. Ships that miscalculated their longitude sailed blind, running onto reefs or surfacing hundreds of kilometers from where they meant to be. In 1707, a British naval fleet ran aground on the Scilly Isles due to a longitude error, killing nearly 2,000 men — a catastrophe that raised the problem to the level of a national emergency.^[11]

Governments began offering enormous rewards to anyone who could solve it. The British Parliament’s Longitude Act of 1714 promised a prize of up to £20,000. The solution came not from a scholar but from a self-taught clockmaker named John Harrison. His marine chronometer, the H4, completed in 1761, accumulated only 5.1 seconds of error over an 81-day voyage.^[12] From that point forward, world maps could finally carry reliable longitude.

From Babylon’s clay tablet to the blood-soaked homecoming of Magellan’s crew, thousands of years of endeavor converge on a single question: what lies beyond the land beneath our feet, and how far does it extend?

Every era found its own way to answer that question — by faith, by calculation, by voyage. Errors bred further errors, and errors opened the door to discoveries. Learning the shape of the world demanded an extraordinary span of time and an extraordinary number of lives.

For readers in Britain, the longitude problem described in the final section carries a particularly close resonance. The Scilly naval disaster of 1707 — in which nearly 2,000 British sailors died because their fleet miscalculated its east-west position — shocked Parliament into passing the Longitude Act of 1714, offering what was then an extraordinary prize of up to £20,000.^[12] The man who finally claimed it, John Harrison, was a Yorkshire carpenter’s son with no formal scientific training. His story became one of the defining episodes of British scientific history, and the four Harrison chronometers he built over a lifetime are still on display at the Royal Observatory in Greenwich — the very site that the world would later adopt as the Prime Meridian.^[12]

But knowing the shape was not the same as finishing the map. How to transfer the form of the world onto a flat sheet of paper — that was a problem of an entirely different order, and it brought its own astonishing distortions and disputes.

Next: Part 2: The Lies of Flat Maps