Columbus in 1492

Christopher Columbus sailed across the Atlantic in 1492, reaching various Caribbean islands about two months after leaving Europe.

Since this was completely unknown territory to Europeans at the time, with no idea of how long before they would reach land - how would they have managed provisions (food and water for the crew)? Would they have expected only a two month journey and prepared for it? Otherwise - if their provisions were half gone with nothing but ocean around them, would they have had to make a decision whether to continue (hoping to find land and provisions before the rest on board ran out), or turn back with the hope of making a future trip with more provisions? Of course - they could have relied on rainwater, birds and fish if supplies were running low.

After 1492, future Atlantic Ocean explorers would know that it would take two months to reach land and plan supplies accordingly. How about other early explorers who had to cross large expanses of unexplored ocean (maybe Magellan?)

Columbus wasn’t sailing off into “parts unknown”. In his mind, he was sailing to China/Japan, and he knew how far away they were because he had carefully calculated the circumference of the Earth and the distance between Spain and China.

Unfortunately for him, he vastly underestimated the circumference of the Earth and overestimated how far East Asia extended. Which meant that he should have run out of supplies and died in the endless ocean, but luckily for him the area between wasn’t empty water - there happened to be a pair of new continents there.

But he didn’t think, “off I go into the great unknown!”. He thought he knew EXACTLY where he was going. He was just wrong.

This is exactly my understanding of the situation. Let me just add that when Jacques Cartier sailed down the St Lawrence river as far as it was navigable, he named the place where he landed La Chine (French name of China) and the place he landed is still called Lachine.

IIRC the story of his voyage, at a certain point the crew was ready to mutiny and turn back. He persuaded them to wait a few more days.

So presumably, they all know how much provisions they had on board and how long they would last. And presumably, too, there was just enough to get home to Spain on reduced rations.

As opposed to Magellan, who re-load in Argentina and Chile, then set out across the Pacific and was reduced to extreme circumstances before they finally found land again.

But contrary to stories about Columbus, the people of the day knew the earth was a globe and knew how big it was, based on Eratosthenes’ calculations. So by then, Magellan had a rough idea how long he might have to go to hit land. He just didn’t realize it would be the maximum - it took 3 months to get to Guam.

Old Chris was turned down by several European monarchs, who took his suggestions to their scientific advisors. Who told them that he was off his rocker. They were right, his proposal was predicated on the circumference of the earth being about a third smaller than it really was. A fact which had been known for about, checks notes 1800 years.
Isabella and whatshisname also turned him down. Until, Columbus spoke privately to a confident of Her Most Genocidal….sorry Most Catholic, Majesty and they agreed. It’s not entirely known what was said, but one operative hypothesis is that Columbus admitted that the smaller circumference claim was bunk, the real reason he wanted to sail west is that he already knew there was land there.
So, if that’s true he had enough provisions for the expected journey.
That Columbus was going because he knew that land was present when the America’s are isn’t a new idea, he was accused of just that in his lifetime.
(This does not necessarily contradict the traditional idea of Columbus persisting in thinking he had found the eastern edge of Asia all the way to his grave, at that time the extent of the Asian continent and its outlying islands wasn’t known to Europeans).

Scholars knew, certainly, but “the people of the day” had no idea who Eratosthenes was and may still thought the Earth was flat.

Yes. their scientific advisors. The educated people knew the Earth was round and more or less how large.

The notion that the unwashed masses still believed the Earth was flat can be laid at the feet of Washington Irving, who decided to write a biography of Columbus and thought the facts were too boring.

I believe around the time of Columbus, most upper class were educated enough to read and write - so it did not fall to just the scholars, most people at court were educated to some degree. (Recall Henry VIII in England 50 years later was to sort to be writing dissertations defending the Catholic Church that earned him commendations from the Pope) Education at the time would involve the classics.

Whether Columbus knew there was land ho! just over the horizon or not is a matter of debate that will never be resolved, I assume. It’s not illogical to assume he knew. If so, why lie to the courts of Europe? I suspect one reason for Isobel was that Portugal had found a way to the Spice Islands via the south of Africa, and so Spain was willing to take a long shot to see if they could out-sail Portugal.

but the point is - most of the sailors had no idea what they would find, so demanded Columbus turn back - presumably while they had enough supplies. Articles say they were seeing flocks of birds, suggesting land was near.

From Britannica -

But by October 10 the crew had begun to lose patience, complaining that with their failure to make landfall, contrary winds and a shortage of provisions would keep them from returning home. Columbus allayed their fears, at least temporarily, and on October 12 land was sighted from the Pinta (though Columbus, on the Niña , later claimed the privilege for himself).

Conclusion - they provisioned enough to go and come back.

Columbus wasn’t going to all the peasants villages in Europe asking them to drum up the cash to send him on his expedition, he was going to royal courts. So the knowledge of the educated elite is what we’re concerned about here.

Yes, that is true.

Actual footage of the conversation

One more charitable read of Columbus is that he relied on a more accurate and recent* Arabic measurement** of the Earth’s circumference than Eratosthenes (which was off by about 15%) but did not realize that the units used were different, which would give a circumference of about what Columbus claimed, although he still has to move Japan much more east for it to work. This incidentally is an issue with Eratosthenes measurements, we don’t exactly know exactly what the “stadia” used corresponded to.

*For some value of recent, it was from 800AD
**For those wondering the Arabic measurement used the Arabic mile, which is indeed about a third bigger than the Roman mile used in Europe, (the Arabic mile survives today as the nautical mile)

No, Columbus relied on the calculations and map of the Italian mathematician and astronomer Toscanelli (1397 – 1482).

It’s amazing how the same questions and misconceptions get rehashed over and over again on the board.

See this recent thread for a long discussion about Columbus.

There also seems to be the same outdated misconception about science and technology in medieval times.

Wikis on

European science in the Middle Ages

Western Europe would see a period of scientific decline during the Early Middle Ages. However, by the time of the High Middle Ages, the region had rallied and was on its way to once more taking the lead in scientific discovery. Scholarship and scientific discoveries of the Late Middle Ages laid the groundwork for the Scientific Revolution of the Early Modern Period.

Medieval technology

After the Renaissance of the 12th century, medieval Europe saw a radical change in the rate of new inventions, innovations in the ways of managing traditional means of production, and economic growth.[2] The period saw major technological advances, including the adoption of gunpowder, the invention of vertical windmills, spectacles, mechanical clocks, and greatly improved water mills, building techniques (Gothic architecture, medieval castles), and agriculture in general (three-field crop rotation).

Nice. Problem for you is that Toscanelli also made the mistake of confusing the Roman and Arabic mile (for a discussion see Beyond the Known by Andrew Rader), in his case using Al-Farghanis calculation that a degree of latitude (and longitude) at the equator was 56 miles, without realising that in this case the “mile” was the 1/3rd bigger Arabic mile. (FWIW, its really about 69 modern miles and 68.7 at the equator).

While I think the best evidence available suggests Columbus genuinely believed getting to the East Indies was a shorter trip than it really was, and further that he continued to believe he had landed on remote islands of the East Indies until his death I was going to mention there are rumors that Columbus knew it was Terra Nova so to speak. There’s some stories out there that suggest there may have been both English and a Spanish crew that in decades immediately prior to Columbus 1492 voyage, ended up in the Western hemisphere and seeing or making landfall briefly, and that Columbus had some knowledge of these trips and wanted to get an expedition to go there but marketed it as the East Indies for financial reasons.

I don’t personally buy it, but thought I’d mention those stories have bounced around for years.

Also why did Columbus choose August to sail ? Was he trying to use the Monsoon winds in India ? (August will be a little late to catch those winds )!

Because it was the soonest he could. Before 1492, Ferdinand and Isabella weren’t willing to sponsor an expedition because they were still busy with the reconquista of Moorish Spain. That was concluded in January 1492, when Granada, the last Arab foothold in the Iberian peninsula, fell. Soon thereafter, the negotiations between him and the monarchs proceeded, and an agreement was reached in April 1492 with the capitulations of Santa Fé, a document (whose legal nature was subsequently disputed in the “pleitos colombinos”, a series of lawsuits brought by Columbus’ descendants against the Spanish crown in the 16th century) that granted Columbus a series of rights and titles. So take April, add a few months for the actual preparations for the voyage, and there you have August. I doubt the monsoon season had anything to do with the timing, as Europeans didn’t have detailed knowledge of South East Asian meteorology at the time. For him, what mattered more was the “volta do mar”, the practice of sailing eastwards in higher altitudes than westwards, to take advantage of the prevailing trade wind patterns. This is indeed a technique Columbus used.

This is the part which I am unable to understand. About 25 BCE Europeans used to travel to India and Indians to Europe, using the monsoon winds. Cite : Periplus of the Erythraean Sea

“The South West monsoon was key for the voyage from the West to India: Ships would leave Egypt in July in order to catch the wind bringing them safely into India in September. If the ship left earlier, in June, it would run the risk of arriving on India’s west coast in August at which time conditions are very hazardous.”

Apparently the seas around the west Indian coast are often very rough in August.

But the Indian monsoon has nothing to do with conditions in the Atlantic. The winds in the Atlantic are totally different, and blow at different times of year.

Right, but if the Americas didn’t exist and Earth was smaller than the Atlantic and Pacific would be one big ocean and presumably the Indian monsoons WOULD affect the Atlantic. Though as was noted Columbus wouldn’t know anything about the Indian monsoons anyways.