What changes are the most likely to significantly delay new world exploration?

[0100010]

And do we have any actual historians backing that up, or just "anyone can write anything on wikipedia"?

http://faculty.ucc.edu/egh-damerow/voyages.htm

[FONT=book antiqua,times new roman,times]The fall of Byzantium to the Ottoman Turks in 1453 disrupted the flow of commerce to Western Europe. Spices, silks, and other luxury items no longer reached Western markets because the Muslims refused to trade with the Venetians and other Westerners. The economic decline of Northern Italy began once the Mediterranean was again dominated by the followers of Islam. The center of trade and commerce shifted to the countries on the Atlantic. First the Portuguese, then the Spaniards, Dutch, French, and English explored the oceans in search of wealth, souls, and glory.[/FONT]

Even before the fall of the Second Rome, Prince HENRY THE NAVIGATOR (1394 - 1460) established a school for sea captains and sponsored naval expeditions down the coast of Africa. Henry was the third son of King John I o Portugal (c.1385 - 1433). Prince Henry was apparently searching for the legendary Christian kingdom of Prester John. He hoped to find an ally against the Muslims and to gain access to African gold through direct trade with sub-Saharan Africa--bypassing Arab middlemen.


The fall of Constantinople merely increased these motivations and added the imperative to find an alternate route to the pepper, nutmeg, and other spices of the Indies.
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http://www.historytoday.com/geoffrey-woodward/ottomans-europe

Portuguese interests were affected both positively and negatively. Portuguese merchants in their search for gold had developed an alternative route to the Far East and Spice Islands that avoided the Turkish controlled east Mediterranean.
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Google Books
I can't easily copy the passage so read it your self.
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http://militaryhistory.about.com/od...ntine-Ottoman-Wars-Fall-Of-Constantinople.htm
I linked to this previous. It also is one of the wikipedia references.
The Author of the article if you click on his profile is a museum professional and historian.

A turning point in Western history, the Fall of Constantinople is seen as the end of the Middle Ages and the beginning of the Renaissance. Fleeing the city, Greek scholars arrived in the West bringing with them priceless knowledge and rare manuscripts. The loss of Constantinople also severed European trade links with Asia leading many to begin seeking routes east by sea and keying the age of exploration.
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http://www.preservearticles.com/201...explorations-in-geographical-discoveries.html

2. Fall of Constantinople:
Europe had enjoyed a flourishing trade and commerce with Asia through Constantinople, the capital of the Eastern Roman Empire, for many years. In 1453 Constantinople fell into the hands of the Ottoman Turks and Europe's trade with the East disrupted.
As the Europeans were very keen to have trade with the East they embarked upon the task of discovering new sea routes. Prof. Webster has rightly observed, "The deed of commerce largely accounts for early explorating voyages. Eastern spices-cinnamon, cloves, nutmeg and ginger-were used more freely in medieval times than now."
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http://www.lessons-from-history.com/history-project-management/15th-century-menu/15th-century

The closure of the trade routes east by the fall of Constantinople (1453) spurs the age of exploration driven by Spain, Portugal.
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Google Books
Again can't copy passage,. 1st two paragraphs under "Causes of European Exploration"
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http://weaponsandwarfare.com/?p=15

The flood of refugees from southeastern Europe, especially Greece, brought thousands of scholars to Italy, further enhancing the peninsula’s Renaissance. Italian merchants, shocked at the prices the Muslims charged for spices and silks from the East, began to search for other ways to get those goods. Certainly the age of European exploration came much sooner because of Constantinople’s fall.

Note the above articles own reference lists of several history books.
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http://www.learnerator.com/ap-european-history/15th-century/age-of-exploration/review/overview

It is important to understand that the primary motivation for these explorations was the search of new trade routes, new trading partners, and new goods to trade. Secondary motives included religious expansion, pride, and satisfying personal curiosity.

Europeans were especially interested in finding new routes to the East for the silk and spice trades.

This was due partly to the fall of Constantinople in 1453 to the Ottoman Empire. With fall of the last remnant of the Roman Empire, Europeans were cut off from direct trade with Asia and thus needed to find an alternative route to the lucrative trade with the “East Indies”.
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http://www.skwirk.com.au/p-c_s-56_u-422_t-1109_c-4282/bartholomew-dias

The pivotal historical event that sparked the onset of the Age of Exploration was the fall of Constantinople in 1453. Constantinople was the capital city of the Byzantine Empire (also known as the Eastern Roman Empire) and the last Byzantine stronghold to be captured by the expanding Ottoman Empire (the Turks) of the East. Located in present-day Istanbul, Constantinople was also an important trading port between Western Europe and the 'mysterious' lands of the East. Before the fall of the Byzantine Empire, the kingdoms of Western Europe had been able to trade goods with India and China along the Silk Road
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http://cuwhist.wordpress.com/worldviews-hist-103/age-of-discovery/

The fall of Constantinople in 1453 severed European trade links by land with Asia leading many to begin seeking routes east by sea and spurred the age of exploration.
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Sufficient?

Sorry, but no. It wasn't Ottoman control of trade routes which sparked westward exploration. It was the looming prospect of Portuguese success to the south that sparked westward exploration.

And the Portuguese began their efforts to round Africa more than a generation before Constantinople fell.

But Ottoman control was one of the main factors the kickstarted most of it, including Portugal's southern explorations.

The Ottoman began closing off Constantinople and thus putting a squeeze on trade long before Constantinople fell and before the Portuguese started looking for southern routes around Africa. This in fact was one of the causes that prompted them to look. As for the rest see above. I'm not saying the powers would not want to cut out the middlemen. There were many factors that pushed exploration, severing the land trades routes was one of them.

Using a middleman has a cost, but like it or not, if that cost remains significantly below the cost of funding and exploring for alternate routes, then one has less financial motivation to look for said alternate. Who the middlemen are, and how much they change directly impacts the decision of whether or not those middlemen are continued to be used.

 

[Elfwine]

(links)

To that, I point out the following:

"The Conqueror knew that his navy was weak, while Venice had obtained favorable terms for trade under an agreement which it had made with the sultan in 858/1454. Freedom of trade was granted to the republic and customs duties at entry and exit was fixed at only two per cent ad valorem. Permission was granted to the Venetians to keep a permanent balio in Istanbul to look after their interests. A similar privilege to trade freely was given to the Genoese in the Archipelago and the Crimea on condition of payment of tribute, i.e. of accepting Ottoman suzerainty. Mehmed the Conqueror recognized the prime importance of trade with the West for his country and his treasury. In 856/143, when broke with the Venetians, he encouraged the Florentines to take charge of trade with Europe.
. . .
After 865/1460 he raised the tariff to four percent for dhimmis, and to five per cent to foreigners from non-Muslim lands (dar al-harb) who were allowed to trade under under treaties of capitulation (sing., aman-name)."

- The Cambridge History of Islam, volume 1A.

Of course, since under what was left of the Byzantine "Empire" the Italian merchant states paid not a wooden nickel, they howled at this. But to say the Ottomans stopped trade or even seriously hindered trade - well, in a word, NO.

 

[Flubber]

But Ottoman control was one of the main factors the kickstarted most of it, including Portugal's southern explorations.

No, it wasn't and the second paragraph in the flood you posted says as much. Let me quote it for you again so you can read it this time:

Even before the fall of the Second Rome, Prince HENRY THE NAVIGATOR (1394 - 1460) established a school for sea captains and sponsored naval expeditions down the coast of Africa. Henry was the third son of King John I o Portugal (c.1385 - 1433). Prince Henry was apparently searching for the legendary Christian kingdom of Prester John. He hoped to find an ally against the Muslims and to gain access to African gold through direct trade with sub-Saharan Africa--bypassing Arab middlemen.

The Ottoman began closing off Constantinople and thus putting a squeeze on trade long before Constantinople fell and before the Portuguese started looking for southern routes around Africa.

No.

The Portuguese began their explorations to A) stop slave raids from northwestern African states and B) to trade directly with gold, ivory, and slave producing areas in western Africa instead via the trans-Sahara middlemen. Portugal had to cut out those middlemen because those middlemen were one and same with the slavers Portugal was attacking.

The Ottomans weren't the ones leading those slave raids and the Ottomans didn't control the trans-Saharan routes. The Ottomans had nothing to do with Portugal's initial efforts along the coasts of Africa.

It was only after Portugal had explored their way to the goods they coveted in the Bight of Benin, colonized the off-shore islands that they found along the way, and the slave trade lured them as far south as Congo/Angola that the idea about rounding the entirety of Africa was deemed both plausible and possible.

This in fact was one of the causes that prompted them to look.

No it wasn't. Prince Henry didn't look east, say herp derp Ottomans, and begin sending out expeditions. Portugal had immediate pressing needs much closer to home, like stopping slave raids and engaging in a little "reconquista" work in northwestern Africa, that drove the initial explorations.

As for the rest see above. I'm not saying the powers would not want to cut out the middlemen. There were many factors that pushed exploration, severing the land trades routes was one of them.

Again, no.

The lands routes were "severed", as you continually exaggerate, in the first half of the 15th Century, yet no one sailed westward until 1492 when it became more and more apparent that the Portuguese project to round Africa was going to work.

The Ottomans had been in control of the trade routes well before they finally buried the Byzantine Empire in 1453, yet no one sailed west for the next forty years. Forty years, more than a generation, and no one did a goddamn thing to find a way around the Ottomans. That's pretty odd considering that "severing" those land trade routes is supposed to such a "spur".

Of course, when Dias returned to Lisbon in December of 1488 to report he'd reached the southernmost point of Africa and the Indian Ocean lay beyond, Columbus was leading a westward exploration voyage across the Atlantic only four years later.

It was the prospect of a Portuguese monopoly due to low prices direct access would grant them and not the continued existence of Ottoman tolls which spurred westward exploration.

 

[0100010]

To that, I point out the following:

"The Conqueror knew that his navy was weak, while Venice had obtained favorable terms for trade under an agreement which it had made with the sultan in 858/1454. Freedom of trade was granted to the republic and customs duties at entry and exit was fixed at only two per cent ad valorem. Permission was granted to the Venetians to keep a permanent balio in Istanbul to look after their interests. A similar privilege to trade freely was given to the Genoese in the Archipelago and the Crimea on condition of payment of tribute, i.e. of accepting Ottoman suzerainty. Mehmed the Conqueror recognized the prime importance of trade with the West for his country and his treasury. In 856/143, when broke with the Venetians, he encouraged the Florentines to take charge of trade with Europe.
. . .
After 865/1460 he raised the tariff to four percent for dhimmis, and to five per cent to foreigners from non-Muslim lands (dar al-harb) who were allowed to trade under under treaties of capitulation (sing., aman-name)."

- The Cambridge History of Islam, volume 1A.

Of course, since under what was left of the Byzantine "Empire" the Italian merchant states paid not a wooden nickel, they howled at this. But to say the Ottomans stopped trade or even seriously hindered trade - well, in a word, NO.

All we are doing is arguing semantics at this point. Increasing the cost of something is still a hindrance where the cost did not exist before or was less. A concept I seem to recognize that you don't. It was a hindrance which was enough to prompt looking for other routes, among other reasons.

No, it wasn't and the second paragraph in the flood you posted says as much. Let me quote it for you again so you can read it this time:

No.

The Portuguese began their explorations to A) stop slave raids from northwestern African states and B) to trade directly with gold, ivory, and slave producing areas in western Africa instead via the trans-Sahara middlemen. Portugal had to cut out those middlemen because those middlemen were one and same with the slavers Portugal was attacking.

The Ottomans weren't the ones leading those slave raids and the Ottomans didn't control the trans-Saharan routes. The Ottomans had nothing to do with Portugal's initial efforts along the coasts of Africa.

It was only after Portugal had explored their way to the goods they coveted in the Bight of Benin, colonized the off-shore islands that they found along the way, and the slave trade lured them as far south as Congo/Angola that the idea about rounding the entirety of Africa was deemed both plausible and possible.

No it wasn't. Prince Henry didn't look east, say herp derp Ottomans, and begin sending out expeditions. Portugal had immediate pressing needs much closer to home, like stopping slave raids and engaging in a little "reconquista" work in northwestern Africa, that drove the initial explorations.

Again, no.

The lands routes were "severed", as you continually exaggerate, in the first half of the 15th Century, yet no one sailed westward until 1492 when it became more and more apparent that the Portuguese project to round Africa was going to work.

The Ottomans had been in control of the trade routes well before they finally buried the Byzantine Empire in 1453, yet no one sailed west for the next forty years. Forty years, more than a generation, and no one did a goddamn thing to find a way around the Ottomans. That's pretty odd considering that "severing" those land trade routes is supposed to such a "spur".

Of course, when Dias returned to Lisbon in December of 1488 to report he'd reached the southernmost point of Africa and the Indian Ocean lay beyond, Columbus was leading a westward exploration voyage across the Atlantic only four years later.

It was the prospect of a Portuguese monopoly due to low prices direct access would grant them and not the continued existence of Ottoman tolls which spurred westward exploration.

Alright, I used the word severed in that sentence because it was still in my head after looked at so many other sources. I recognize using that word is an exaggeration. Trade still existed but, I still say that these sources say it was reduced, because of price increases and the 'hindrance' that represented.

You though still ignored the 3rd paragraph

The fall of Constantinople merely increased these motivations and added the imperative to find an alternate route to the pepper, nutmeg, and other spices of the Indies.

It had a factor which increase looking for trade via other routes, which includes increasing the importance of looking south.

I've never said Ottoman control of trade through their lands was the only cause I've said it was one among many.

So from all this I could add a couple more items to ways in which to delay westward expansion by European powers.

1) Sabotaging Portuguese southern exploration along Africa.
2) Enable easier (and less expensive) land route access over the Sahara and/or control of North Africa, so the voyages have less importance.

What is your opinion on those?

 

[Elfwine]

All we are doing is arguing semantics at this point. Increasing the cost of something is still a hindrance where the cost did not exist before or was less. A concept I seem to recognize that you don't. It was a hindrance which was enough to prompt looking for other routes, among other reasons.

There is a huge difference between a very light custom duty and the Ottomans "not being open to trade", "barring Europeans", "disruption" of existing routes, or anything as serious as claimed.

This isn't semantics, this is apples and mushrooms. Or maybe apples and giraffes.

For the powers other than the Italian merchant republics the Italians as middlemen are far more problematic than the tiny amount the Ottomans are influencing prices.

Which brings us to the fact that as Flubber has pointed out, people looked for other routes for reasons having nothing to do with 1453.

 

[riggerrob]

There is a huge difference between a minor trade tarrif and the vast difference between the cost of camels and the cost of ships. Moving goods by ships costs somewhere between 1 percent and 10 percent the cost of moving the same goods overland. It was not until the invention of railroads that land transportation could even pretend to compete with the cost of shipping. Even today, shipping is by far the cheapest way to move goods long distances.