Phillips, William D.  Medieval Origins of European Expansion.  James Ford Bell Lectures, No. 33 (June 1995).  The Associates of the James Ford Bell Library:  University of Minnesota, 1996.

Phillips' short talk is a remarkably compact summary of major trends in European trade.  His thesis is as follows:

Europe's dreams of the wealth of Asia and its merchant's hopes of tapping that wealth at its source had motivated Europeans for centuries during the later Middle Ages.  From the time of the Crusades, Europeans had probed the possible routes:  unsuccessfully for the Indian Ocean route, temporarily for the Silk Road at the time of the Mongol ascendancy, and -- at last-- successfully for the high seas routes.  Portuguese vessels in the Atlantic and the Indian Ocean and Spanish vessels in the Atlantic and the Pacific, and the regular commerce they maintained, were the realities that emerged from the medieval dreams. (22)

He starts with the Roman-Chinese Silk trade route.  He follows Europeans in the early Middle Ages as they go on Crusades, try to get past the Mamluk blockades, visit the Great Khan, sail past the pillars of Hercules, and as often as not, don't make it back.  Picking up with Portuguese trade down the coasts of Africa, and the conquest of the Canaries and the Philippines, he suggests a sharp rivalry between Portugal and Span for the key route East, around the Arab middlemen. Both countries found a route; one below the Cape of Good Hope to India, led by Vasco Da Gama in 1499, and the other across the Pacific, led by Magellan from 1519 to 1522.

I am not sure if his story makes "sense" in that I doubt that all of these disparate groups were motivated by the same dream.  However, for a short summary of exploration and trade, you could hardly do better.