(Cotterell 58-60) Trade flourished under the Yuan dynasty, and through their years of ruling, they permitted merchants to trade freely throughout the Yuan's empire. They controlled the entire silk road, trade routes that run through Northern China across Asia. Caravans had helped International trade thrive because caravans could travel without trade. Chinese merchants had gained large fortune through the trades of silk, spices, teas, porcelain, and lacquerware. Trades were also helped spread because of Marco Polo, who went to China. He wrote about his travels to China, and this increased cultural diffusion.