Why Did Columbus Think He Had Reached India?

He was about 102º off. Why would such a brilliant navigator make such a huge mistake?

Perhaps the most significant event in the spread of Europeans thoughout the world, the credited discovery in the 13th Century by Christopher Columbus, the renowned Italian navigator financed by the Spanish royal house of Castile. Despite contemporary source that suggested otherwise and the work of Eratosthenes some centuries before, he firmly believed that Cathay only lay 3900 miles west of Europe. Why was he so convinced of this?

The Need for an Sea Route

By the late 1400’s, the existence of what we would today call India and China were known to explorers and traders. The trade route, however, was entirely over land, traversing areas known for thier extremes of climate and the endurance that such required. Also, those land based trade lanes, such as the Silk Road, passed through territory held by rulers of many people. These factors combined to make the journey arduous and dangerous, and above all, expensive–a feat to be undertaken only by those with already considerable resources.

It was known by this time that the world was round, or spherical, and was suspected that if one sailed into far enough into the far reaches of the western ocean that eventually one would reach the resource rich areas known then as the “Indies”, completely obviating many of the hazards of overland travel. Anyone who could pull off such a feat would rightly expect fame, immense fortune, and great favor from whichever world power on who’s behalf it would have been done.

Enter Columbus

Christopher Columbus had already earned a reputation as an accomplished seaman and navigator.
Selling the idea of venturing into the west was tough for him, having consumed his life during the decade of 1482-1492. In 1482, he had sailed to the remotest southern extent of the then-known world, a Portuguese trading post known as Mina on Africa’s Gold Coast. He is reputed to have then seen flotsam – plant matter and wood that appeared to have been worked – coming his was from the western horizon, something that could have only been possible from lands in the west.

He also studied Claudius Ptolemy’s ancient map of the world. This map (illustrated here) covered the oecumene and was a commonly accepted (and updated) reference. There was still a flaw, however; the map appared to extend Asia to cover an area actually occupied the then-unknown Americas and the Pacific.

Columbus’s Evidence

Though flawed by today’s standard in that way, Ptolemy’s work held that the oecumene, which then comprised essentially Europe, Asia, and coastal regions of northern Africa, comprised 180 degress of the terrestrial circle. It was thought that, at the time, the area between western Europe and eastern Asia was all ocean, impassable by its sheer size. So large was this body of water that no ship could be built with the current technology that was both fast enough and could carry sufficient provisions to survive the crossing.

A modern approximation of the Ptolemaic map Columbus used (produced with Geocart)

Columbus, however, preferred the views of Roman Catholic cardinal Pierre d’Ailly (1350-1420). His cosmology, Imago Mundi, held that the oecumene occupied not 180º of the earth’s circumference but 225º, leaving 135º as ocean. Further, he believed that one degree of longitude represented 56.6667 miles (shorter than the commonly accepted value), and the miles he used were Roman miles (1,524 meters/5,000 feet) rather than nautical miles (1,853.99 meters/6,082.66 feet).

The dimensions of the globe Columbus arrived at were, at its greatest curcumference, about 19,000 modern statute miles or 30,600 km, putting the distance from the Canary Islands to Japan at only about 2,400 nm (4,444 km). Perhaps most surprising is that this master navigator looked to a spiritual source even higher than the Cardinal d’Ailly for final confirmation; the apocryphal Biblical Second Book of Esdras. From his ill-starred fourth voyage of 1502, the explorer wrote his patrons:

In the carrying out of this enterprise of the Indies nether reason nor mathematics nor maps were any use to me. Fully accomplished were the words of [the prophet] Isaiah.

For a man who was an acknowledged genius at finding his way around based on phyiscal evidences, this juxtaposition of science and superstition is jarring, to say the least.

Welcome to the Indies?

The result speaks for itself: Columbus’s information led him to believe that Asia lay merely 78º west of Spain. Needless to say, India was exactly not what he came upon in the last decade of the 13th Century, but rather what we today call the “West Indies”, since the name stuck; the aboriginal American population became known as “Indians” for this reason.

Despite not having found a route to Asia (though it is said that Columbus went to his deathbed believing that he in fact had), the European exploration of the “New World” resulted in thereto unparalleled power, prestige, and empire for the great European seafaring nations of the day, Columbus died wealthy (though in some disrepute) because of the spoils of his activity, and is continued to be celebrated as a hero amongst European-descended populations of the New World.

Bibliography and Sources:

• 100 Maps: The Science, Art, and Politics of Cartography Througout History, John O.E. Clark, ed; pp 98-99; Sterling Publishing, Toronto 2005, ISBN 1-4027-2885-9
• Wikipedia article on Christopher Columbus at http://en.wikipedia....Christopher_columbus
  
• Wikipedia articl on Pierre d’Ailly at http://en.wikipedia.org/wiki/Pierre d’Ailly