“Paper money, virtually unknown in the West until Marco’s return, revolutionized finance and commerce throughout the West. Coal, another item that had caught Marco’s attention in China, provided a new and relatively efficient source of heat to an energy-starved Europe. Eyeglasses (in the form of ground lenses), which some accounts say he brought back with him, became accepted as a remedy for failing eyesight. In addition, lenses gave rise to the telescope—which in turn revolutionized naval battles, since it allowed combatants to view ships at a great distance—and the microscope. Two hundred years later, Galileo used the telescope—based on the same technology—to revolutionize science and cosmology by supporting and disseminating the Copernican theory that Earth and other planets revolved around the Sun. Gunpowder, which the Chinese had employed for at least three centuries, revolutionized European warfare as armies exchanged their lances, swords, and crossbows for cannon, portable harquebuses, and pistols. Marco brought back gifts of a more personal nature as well. The golden paiza, or passport, given to him by Kublai Khan had seen him through years of travel, war, and hardship. Marco kept it still, and would to the end of his days. He also brought back a Mongol servant, whom he named Peter, a living reminder of the status he had once enjoyed in a far-off land. In all, it is difficult to imagine the Renaissance—or, for that matter, the modern world—without the benefit of Marco Polo’s example of cultural transmission between East and West.”