I’d say that batsto has explained themselves clearly from the start - that books on the subject about exploration appeared to be either overstating technological advances or failing to accurately describe said advances. Also, when people mentioned the Longitude book here, it’s like answering a question on long distance communication during the Napoleonic Wars by recommending a book on field radios.
Seb Falk talks a bit about this in The Light Ages.
The compass was known in Europe by the late 12th century at least. The compass made it possible to create portolan charts. (It’s very difficult to draw an accurate map without a compass.) Combining a growing body of portolan charts made it possible to create accurate maps of the whole Mediterranean by the 14th century, then the Atlantic islands and down the coast of Africa in the 15th century.
From about 1200, there are mentions in texts of navigating by the north star. I guess even if it was a few degrees off it was useful.
The Portuguese adapted standard astrolabes to create mariner’s astrolabes to measure latitude accurately on voyages out of sight of land.
I’d say that batsto has explained themselves clearly from the start - that books on the subject about exploration appeared to be either overstating technological advances or failing to accurately describe said advances.
Yeah, that part makes sense. In fact, I agree with batsto about that. And I agree that the book I chimed in on addressed a time period way after the 15th century timeframe mentioned in the OP. The book doesn’t address the question—mea culpa.
What I don’t understand is why the two novel combinations I mentioned don’t partially answer the question.
Novel combinations like this are often big technological leaps. Early in WWII, we had radar and we had fused anti-aircraft shells, but radar-powered proximity fuses (and radar-driven gun laying) worked a whole lot better than radar-free versions. It was a novel combination of two known technologies, and it was wildly successful.
You could say the same about tungsten (known) and light bulbs (also known). Combining these two known items resulted in a really durable bulb that helped popularize electric lighting. I could go on and on about other combinations.
I outlined the combinations in question in some detail above. They probably don’t account for the technological leap alone, but they seem like likely candidates for some of it.
I really don’t mean to harp on this (despite all appearances to the contrary). The history and philosophy of science/applied science are pet interests of mine—especially popular understandings of technological changes.
I’m curious about whether the OP is rejecting the combination of two known things because that seems inherently non-novel. I’m also interested in the full answer to the OP’s question myself, because I wonder whether the historians who handwave about a big advance without going into detail are simply repeating the handwaving of others in a cyclical way.
I don’t mean to heckle the OP or, for that matter, make them the guinea pig in my personal idea lab. I’m just sort of excited and curious, which is sometimes hard to distinguish from heckling. If that’s the case here, I apologize.
The discovery of ocean and wind currents and how to sail them out into the Atlantic.
The discovery of the Azores and Canaries as staging posts out into Atlantic.
Some confidence that you could sail west into the Atlantic exploring and later sail north to pick up the prevailing westerlies to take you back to Spain and Portugal.
Riding the circular currents in the North and later South Atlantic gyres was the key to oceanic travel. Starting with more localised currents such as the Canaries current.
But facing the wild Atlantic Ocean was a reaction to economic necessity of finding some way around the Ottoman and Venetia monopoly on trade with the East.
The sailing conditions in the Mediterranean were somewhat different, where you were unlikely to be out of sight of land for many days and sets of oars were pretty handy for coast hugging journeys.
The political and economic drivers are often ignored. The US did not devote so many resources into getting to the moon in the 1960s because scientists thought it might be an interesting idea. It would never have happened without the Cold War rivalry with the USSR. But then nor would we have had the technological spin offs such as the semi conductor industry necessary for aeronautic control systems and communication. That led to satellite TV, the Internet and the multi media wonderland that plays such an important part of modern life.
The 15th century equivalent was the development of sailing technology and navigation. It was born out of economic necessity and international politics. The dividend was the power projection that comes with ocean going expeditions first for exchange or plunder. Then later plantation, colonies and trade and the naval capability to protect those assets from rival states.
The combination of economic and political drivers with technology advances at points in history is fascinating. Would ocean going sailing have developed if the only economic driver was fishing? I think Henry the Navigator of Portugal had a bigger prize in mind to devote state resources to exploration: trade with India and China. Ship design had to be adapted for exploration and the effective use of sail and sea currents across the ocean. From the Portuguese caravel to the Spanish galleon. From Sputnik to SpaceX? It takes a while for the economic drivers and the technology to coincide.
Earlier maps likely only followed coastal features, crossing seas out of sight of land would have been less certain. Portolan charts developed in 13thC began to show headings between geographical points and could be used to navigate direct routes across the Mediterranean. No doubt this technology was much improved over time.
Yes, because that was when magnetic compasses became available.
And there’s even an episode of The Day the Universe Changed that’s about this. The show is even on Archive.org for free to watch.
The Apollo missions may have accelerated some technology by a year or two but that is about it. The Apollo fight control computers were marvels of technology on the bleeding edge, but they were based on (just) existing technology pushed to the limit. Providing a lucrative market for some of the very early integrated logic circuits probably helped the business, but they were developed independently of Apollo.
The NASA’s foray into computerised flight control was probably accelerated a few years by Apollo, since they used the Apollo guidance computer hardware (and famously even used space flown components.) But once they had the experience, commercial compute hardware was already well on the way to being small enough.
Sadly, in terms of space technology, once you get past the insane push of Apollo, you could argue that Apollo actually set the US space programme back. So much money vanished into manned space technology. It isn’t as if other nations were not also developing their own related technologies either. The world didn’t have to wait for the USA to work this stuff out. Nor in most cases did they wait.
Portolan charts are not the same thing as what we would consider maps, and this is an importnat distinction in the history of navigation.
A Portolan chart does not have a direct geometric relationship to the actual layout of the Earth. For a start it is flat. But most importantly its critical information content are the compass courses to be sailed in order to get from place to place. So the lines are Rhumb Lines (aka Loxodromes). A Rhumb line is not usually a straight line on the surface of the Earth. The result is that the Portolan chart is a symbolic representation that roughly fits the layout of the region. You don’t navigate a Portolan Chart with latitude and longitude. It is more like the London Underground map, it tells you how to get from A to B so long as you use the tracks (compass courses) it defines. If you wander off-piste, you may have some rough idea how to get to where you need, but there be dragons in the gaps between the lines. These charts would be generated incrementally by experience.
So these charts represent a really important stepping stone on the way to modern navigation.
Eventually the need for maps with a more rigorous geometry became apparent. So maps with defined geometric projections replaced these charts. Mercator projection being the useful one because you could draw straight lines on the maps and steer a single compass bearings to match it. But that brought about the need to have an idea of where you were spatially, and hence the whole longitude problem.
As to the chronometer, that was indeed a pivotal invention. Until the advent of GPS, navigation really didn’t advance much. Sailors even a few decades ago were expected to be able to navigate with compass, sextant and chronometer. Some still keep the skills alive. (Decca/Loran is in there, and still exists in a few places, arguably not for any good reason, but that was a minor blip. Omega is gone.)
Surely a rhumb line is a straight line on a Mercator projection. So if you have sailing directions like ‘If you sail directly SSE from port A, you’ll get to port B’, and you draw a map based on those sailing directions, the map you will get will be a Mercator projection?
sorry, I fell asleep before I saw any of this.
I don’t mean to come across as rejecting any of this–I’m not. I was just looking for more information; I was always under the impression that there were quite a few advances made, and I feel like if this was the whole answer, then everyone would just point to that one thing and say ‘because of this’, rather than making it seem like there were numerous important inventions.
And I’ll be checking this out today, thanks!
Interesting thread. I was thinking about other innovations not directly related to navigation or sailing techniques. Perhaps inventions in logging and lumbering could have enabled the design and building of larger ships capable of sailing across the oceans and back? Were there any new tools for sawing larger logs, or felling taller trees to be used as masts, and transporting them to ports? Perhaps advances in other materials used for preserving wood in salt water? Or for that matter, ship design evolution in general, such as hull shape. I don’t know when some of these other advances may have occurred, or if they played a role in the age of exploration.
Well now you’ve got me wondering too—I hadn’t considered most of these. But the bit about ship design and hull shape was addressed (see the posted links above about the caravel, for instance). So now we need someone here who knows a lot about lumber history…
I have the book of the series open in front of me. Burke states that the other big development in sailing during the period was Toscanelli’s use of a grid system to overlay a map of the world, specifically Ptolemy’s Geographica. This would be rather…important.
“With Toscanelli’s map tucked to the flyleaf of his atlas, the captain set sail for Japan. He was never to arrive. On the way west to Japan Captain Columbus discovered America.” - “Point of View”, The Day The Universe Changed, James Burke
I suspect most if not all of these inventions and innovations owe more to the Age of Discovery than the other way around. Those greedy European mariners were going to get to and from the riches of Asia and America whether or not they had compasses, lateen sails, and long timbers.
Even if compasses already existed long before that, there are compasses and then there are compasses. It’s a significant leap from a sliver of iron floating on a cork, to a modern navigational compass that gives you a precise bearing.
Just finished watching the Burke episode posted above, and it was very informative. I haven’t watched any of his stuff in a long, long time and forgot how great it was.
sorry, I fell asleep before I saw any of this.
I don’t mean to come across as rejecting any of this–I’m not. I was just looking for more information; I was always under the impression that there were quite a few advances made, and I feel like if this was the whole answer, then everyone would just point to that one thing and say ‘because of this’, rather than making it seem like there were numerous important inventions.
Thanks for your clarifying reply. I agree with you that those combined technologies are unlikely to be the the whole story, and may in fact be a relatively small part of the story—I don’t have the expertise to say.
Thanks again for responding. Your perspective makes a lot more sense to me now—cheers!
Perhaps the premise is flawed. That is, maybe it wasn’t technological advances originating in the 15th century that prompted the age of discovery, but rather advances predating the 15th century permitted voyages of discovery to begin in earnest once there was a need for such a thing, with sufficient technology and skill in the use of such technologies having already been amassed prior to the 15th century.
Coincidental to reading through this thread yesterday, I just (right now, as of posting) finished part two of the Fall of Civilizations podcast/youtube series episode on Byzantium. One thing noted in the conclusion was the possible influence of the fall of the Byzantine Empire to the Ottomans in the mid-15th century. That effectively removed a major east-west trading hub and, as the conclusion posited, led to the immediate need for alternate trade routes.
So, as this alternate hypothesis goes, the technology for sea voyages to Asia already existed at the dawn of the 15th century. It’s just that up until the fall of the Byzantine Empire there was no need to seek out routes around Africa or–gasp–circumnavigating the globe to gain access to the Indian ocean and Asia directly. Ptolomey’s Geographia, which @silenus already mentioned as influential on 15th century navigators, only just reached western Europe from Constantinople in the 15th century, and was also mentioned in the Fall of Civilizations episode as a major influence on Columbus specifically, contributing in part to his misconception of the circumference of the Earth.