The world of Indian Ocean commerce was long in the making, dating back to the time of the First Civilizations. Seaborne trade via the Persian Gulf between ancient Mesopotamia and the Indus Valley civilization is reflected in archeological finds in both places. Perhaps the still-undeciphered Indian writing system was stimulated by Sumerian cuneiform. The ancient Egyptians, and later the Phoenicians, likewise traded down the Red Sea, exchanging their manufactured goods for gold, ivory, frankincense, and slaves from the coasts of Ethiopia, Somalia, and southern Arabia. These ventures mostly hugged the coast and took place over short distances. Malay sailors, however, were an exception to this rule. Speaking Austronesian languages, they jumped off from the islands of present-day Indonesia during the first millennium B.C.E. and made their way in double-outrigger canoes across thousands of miles of open ocean to the East African island of Madagascar. There they introduced their language and their crops—bananas, coconuts, and cocoyams—which soon spread to the mainland, where they greatly enriched the diets of African peoples. Also finding its way to the continent was a Malayo-Polynesian xylophone, which is still played in parts of Africa today.

The tempo of Indian Ocean commerce picked up in the era of second-wave civilizations during the early centuries of the Common Era, as mariners learned how to ride the monsoons. Various technological innovations also facilitated Indian Ocean trade—improvements in sails, new kinds of ships called junks with sternpost rudders and keels for greater stability, new means of calculating latitude such as the astrolabe, and evolving versions of the magnetic needle or compass.

Around the time of Christ, the Greek geographer Strabo reported that “great fleets [from the Roman Empire] are sent as far as India, whence the most valuable cargoes are brought back to Egypt and thence exported again to other places.”13 Merchants from the Roman world, mostly Greeks, Syrians, and Jews, established settlements in southern India and along the East African coast. The introduction of Christianity into both Axum and Kerala (in southern India) testifies to the long-term cultural impact of that trade. In the eastern Indian Ocean and the South China Sea, Chinese and Southeast Asian merchants likewise generated a growing commerce, and by 100 C.E. Chinese traders had reached India.

The fulcrum of this growing commercial network lay in India itself. Its ports bulged with goods from both west and east, as illustrated in the Snapshot. Its merchants were in touch with Southeast Asia by the first century C.E., and settled communities of Indian traders appeared throughout the Indian Ocean basin and as far away as Alexandria in Egypt. Indian cultural practices, such as Hinduism and Buddhism, as well as South Asian political ideas began to take root in Southeast Asia.

In the era of third-wave civilizations between 500 and 1500, two major processes changed the landscape of the Afro-Eurasian world and wove the web of Indian Ocean exchange even more densely than before. One was the economic and political revival of China, some four centuries after the collapse of the Han dynasty. Especially during the Tang and Song dynasties (618–1279), China reestablished an effective and unified state, which actively encouraged maritime trade. Furthermore, the impressive growth of the Chinese economy sent Chinese products pouring into the circuits of Indian Ocean commerce, while providing a vast and attractive market for Indian and Southeast Asian goods. Chinese technological innovations, such as larger ships and the magnetic compass, likewise added to the momentum of commercial growth.

A second transformation in the world of Indian Ocean commerce involved the sudden rise of Islam in the seventh century C.E. and its subsequent spread across much of the Afro-Eurasian world (see Chapter 9). Unlike Confucian culture, which was quite suspicious of merchants, Islam was friendly to commercial life; the Prophet Muhammad himself had been a trader. The creation of an Arab Empire, stretching from the Atlantic Ocean through the Mediterranean basin and all the way to India, brought together in a single political system an immense range of economies and cultural traditions and provided a vast arena for the energies of Muslim traders.

Those energies greatly intensified commercial activity in the Indian Ocean basin. Middle Eastern gold and silver flowed into southern India to purchase pepper, pearls, textiles, and gemstones. Muslim merchants and sailors, as well as Jews and Christians living within the Islamic world, established communities of traders from East Africa to the south China coast. Efforts to reclaim wasteland in Mesopotamia to produce sugar and dates for export stimulated a slave trade from East Africa, which landed thousands of Africans in southern Iraq to work on plantations and in salt mines under horrendous conditions. A massive fifteen-year revolt (868–883) among these slaves badly disrupted the Islamic Abbasid Empire before that rebellion was brutally crushed.14

Beyond these specific outcomes, the expansion of Islam gave rise to an international maritime culture by 1000, shared by individuals living in the widely separated port cities around the Indian Ocean. The immense prestige, power, and prosperity of the Islamic world stimulated widespread conversion, which in turn facilitated commercial transactions. Even those who did not convert to Islam, such as Buddhist rulers in Burma, nonetheless regarded it as commercially useful to assume Muslim names.15 Thus was created “a maritime Silk Road . . . a commercial and informational network of unparalleled proportions.”16 After 1000, the culture of this network was increasingly Islamic.