"The plague was an epidemic of commerce. The same Mongol roads and caravans that knitted together the Eurasian world of the thirteenth and fourteenth centuries moved more than mere silk and spices."
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With the luxurious fabrics, exotic flavors, and opulent jewels, the caravans brought the fleas that spread the plague from one camp to another, one village to another, one city to another, and one continent to another.
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The plague effectively destroyed the social order that had dominated Europe since the fall of Rome, leaving the continent in dangerous disorder.
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The Mongol Empire depended on the quick and constant movement of people, goods, and information throughout its massive empire. Without those connections, there was no empire."
No Genghis Khan and the Making of the Modern World, grāmatu, ja kas, iesaku.