What factors led to the increase in global trade from the 1200s to the 1500s?

Question: What factors led to the increase in global trade from the 1200s to the 1500s!?
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One very important factor was the development of the sextant and compass!. Navigation was a pretty hit or miss affair prior to that, but with the navigational aids, captains could chart a course!. Of course, they thought the world was flat at that point in time, so they still had a few little glitches!.!.!.!.!.!.Www@QuestionHome@Com

I might also include the reign of the Mongols!. Following the conquest of much of Asia, the trade routes were secured for licensed traders!. If a person had a pass for his caravan from the Great Khan, anybody that messed with that caravan was in for some serious pain!.Www@QuestionHome@Com