Goods, Skills and Sickness on the Move
1Between about 600 and 1450 CE, three great networks of trade linked Asia, Africa and Europe. Overland Silk Road routes joined China to Central Asia, Persia and the Black Sea. Sea lanes across the Indian Ocean joined China, Southeast Asia, India, Arabia and East Africa. Camel caravans on trans-Saharan routes joined North Africa to West African cities such as Timbuktu. Few traders made a whole journey. A load of silk or pepper usually changed hands many times, city by city.
2Goods could move this way because any trader could carry them. A skill was different. Bolts of Chinese silk reached the Mediterranean long before the method of raising silkworms left China. In the same way, Chinese workers had made paper from tree bark, hemp and old rags since at least the 100s CE, but the method of making it spread only when people who knew it moved and taught others. It reached Korea and Japan by the early 600s and Central Asia in the 700s.
3In the Muslim world, paper caught on quickly. Scribes there had written on papyrus, a reed that grew mainly in Egypt, or on parchment, made from animal skins; a large book could need the skins of dozens of animals. Paper could be made from plant fibers and rags in many places. By about 800, Baghdad had paper mills, and government offices, merchants and scholars used paper for records, letters and books. Papermaking then spread west across North Africa to Muslim Spain. Christian Europe's first paper mills were in Spain and Italy, and caravans later carried paper south across the Sahara to the scholars of Timbuktu.
4Travelers spread ideas too. The Venetian merchant Marco Polo spent years in China under the Mongol ruler Kublai Khan. His book described coal, porcelain and paper money, and some European readers doubted that such things could exist. Muslim merchants who settled in ports around the Indian Ocean helped spread Islam to many coastal towns, and they kept accounts and wrote contracts on paper.
5Diseases moved along the same paths. In 1346 plague broke out among soldiers attacking Caffa, a Black Sea trading port run by merchants from Genoa, Italy, and inside the town as well. Genoese ships soon carried it to Constantinople and to Sicily. Historians think fleas on rats aboard ships and in stored grain, along with sick sailors and travelers, carried it from port to port.