This is a map of the muslim world. Before islam, Europe traded with people all the way into India and China. India, China, and everything in between was known from the time of Alexander the Great.
Then islam expanded and cut off the trade routes between Asia and Europe, especially the Silk Road. You can see that in the map. Europe was isolated from other civilizations, and this was a big part of why they fell into a dark age. Look at how small Europe is compared to the muslim world. Muslims had all the advantages of trade and wealth. They would have absorbed Europe eventually.
This is a map of the voyages of discovery. Once Europe had recovered from the dark ages enough, and Spain had fought off the muslim occupiers, they developed an Apollo program to find an alternate, sea route to Asia in order to re-establish trade, without going through muslim territory. Compare the two maps, look at the areas the Europeans are deliberately avoiding.
The gamble succeeded beyond anyone's wildest dreams. Not only did they re-establish trade, they discovered two large continents uninhabited by muslims, which they could colonize. The Christian world became larger and more wealthy than the muslim world. The muslim world lost their caliphate, and fell into their own dark age. Now they live in boundaries drawn by Europeans. Only the discovery of oil has given them any relevance at all, and when that goes, they will fade away.