Happy Columbus Day! (With a little history lesson)

Most of us know the little rhyme from our earliest schooldays: "In 1492, Columbus sailed the ocean blue."

But why did Columbus need to find a new route for the spices which Europe so craved?
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From Citizen Warrior:

But why was [Columbus] looking for a trade route? Because during its second great jihad, Islam had invaded Central Asia and defeated Constantinople in 1453, cutting off the overland route for Europeans. Islamic armies continued their jihad northward, and conquered much of what is now Eastern Europe, until they were finally stopped at the gates of Vienna in 1529.

How many history textbooks today dare to tell those facts?

More information at Jihad Through History.