The Maritime Silk Road — The Silk Road Atlas

The phrase “Silk Road” most often evokes caravans of camels crossing the Taklamakan Desert and the Pamir Mountains. Yet for almost as long as there has been an overland silk trade, there has also been a sea trade, and for many of the goods in transit — porcelain, pepper, timber, salt — the maritime route was the more important of the two. The Indian Ocean, the South China Sea, the Strait of Malacca, the Persian Gulf, and the Red Sea together formed a network of sea lanes as busy, as technically sophisticated, and as politically charged as any overland corridor. To study the Silk Road without the maritime trade is to study half a system.

This article surveys the maritime silk trade from its origins in the early centuries CE to the era of European naval dominance in the seventeenth. It treats the geography of the routes, the ships that sailed them, the cargoes they carried, the merchants who organised them, and the political forces that shaped them. For the broader context of long-distance commerce, see the article on Silk Road trade, goods, and economy. The complementary overland network is described in the article on the routes and geography of the Silk Road, and the great port cities that linked sea and land are surveyed in the article on Silk Road cities. The single most consequential maritime episode in Silk Road history, the Chinese treasure voyages of the early fifteenth century, is treated in the article on Zheng He’s voyages, and the eventual European takeover of the maritime trade is described in the article on the Age of Discovery and the Silk Road. The principal commodity carried by the maritime route is treated in the article on the spice trade.

The geography of the maritime routes

The maritime Silk Road was not a single route. It was a network, and its shape was set, more than by anything else, by the monsoon. From at least the early centuries CE, Indian Ocean mariners understood the rhythm: the southwest monsoon, blowing from June to September, made it possible to sail from Arabia to India in a single season; the northeast monsoon, blowing from November to February, brought you back. That two-wind system governed trade across the entire Old World, from the Swahili coast to the South China Sea, and it is, in my view, the single most important fact about pre-modern Indian Ocean commerce. Everything else — the emporia, the cargoes, the port cities — is downstream of the wind.

The principal nodes of the network can be sketched briefly. On the western end, the trade was organised from the ports of the Persian Gulf, particularly Siraf in the early medieval period and Hormuz in the later, and from the Red Sea ports of Aydhab and Aden. Goods from these ports were transshipped by caravan to the Nile, and from there by river boat to Alexandria and the Mediterranean, or carried by overland caravan to the Levantine ports of Beirut, Acre, and Tyre. I have walked the breakwater at Siraf, or what is left of it, and the thing that strikes you is how small the actual port is — a hundred metres of quay, tops. The trade it organised was anything but small.

The Indian subcontinent formed the middle of the system. The principal western Indian ports — Barygaza (modern Bharuch), Calicut (Kozhikode), Quilon (Kollam), and Cambay (Khambhat) — were the emporia from which pepper, cinnamon, gems, and textiles were distributed east and west. Further east, the network passed through the Strait of Malacca into the South China Sea, with major ports at Srivijaya (near modern Palembang, Sumatra), at the Thai port of Tambralinga, and at the Champa ports of central Vietnam. From there, junks sailed north to the Chinese ports of Canton (Guangzhou), Quanzhou, and Hangzhou. The standard view is that the pivot of the whole system was the Strait of Malacca. The standard view is probably right.

Ships won. The camels did not stand a chance.

The principal Chinese goods moved by sea, especially in the later periods, were silk, porcelain, tea, and metal goods. The principal Southeast Asian and Indian goods were pepper, cloves, nutmeg, mace, cinnamon, sandalwood, gems, and textiles. West Asian and African goods included frankincense, myrrh, ivory, gold, and slaves. What strikes me about the cargo list is how much of it is low-value-by-weight, high-value-by-volume — the trade was always going to favour the ship over the camel, on sheer physics, and the maritime share grew accordingly.

Ships and seamanship

The ships of the maritime Silk Road varied enormously with region, but a few general types dominated. In the western Indian Ocean the workhorse was the dhow, a term that covers a wide range of Arab-built vessels with one or more lateen sails. The lateen rig, with its triangular sail set on a long yard at an angle to the mast, allowed the dhow to tack against the wind — a major advantage in the variable breezes of the Indian Ocean. The largest dhows, with crew complements of thirty or more, could carry several hundred tons of cargo, which is more than most people imagine when they picture a “dhow.” I think the lateen rig is, technically, the most underrated invention in the history of sailing.

In Chinese waters, the standard vessel was the junk, a flat-bottomed ship with a distinctive battened lug sail and a high stern. Chinese shipbuilding reached a high technical level in the Tang and Song dynasties, and the largest junks of the thirteenth and fourteenth centuries — those described in detail by Marco Polo and other visitors — were among the most impressive wooden ships ever built. The compartments that divided the junk’s hull into separate watertight sections, a Chinese invention of perhaps the second century CE, gave the type a survival rate that impressed every foreign observer. Popular accounts tend to overstate the size of the Zheng He treasure junks; the actual excavated specimens at Nanjing are impressive, but they are not the 400-foot monsters of the older literature.

In Southeast Asian waters, a different set of vessels was used, including the large, oared warships of the Majapahit and Srivijaya thalassocracies, and the smaller perahu used by Bugis and other seafaring peoples of the archipelago. Indian Ocean trade also relied on a fleet of smaller coastal vessels that carried goods between the great emporia and the smaller ports up and down the coasts of Arabia, India, and East Africa.

Navigation was by stars, sun, and the rhythms of the monsoon, with the addition, by the later medieval period, of the mariner’s compass, which the Chinese had developed by at least the eleventh century. The earliest extant description of a magnetic needle used for navigation is the Chinese writer Shen Kuo’s account of c. 1088 in the Dream Pool Essays (Mengxi Bitan), and the technology spread westward through the Islamic world and into the Mediterranean during the twelfth and thirteenth centuries. A point that is often missed: the compass did not, on its own, revolutionise Indian Ocean navigation, because the monsoon system was already well understood. What it did was make the navigation more reliable, especially on the cloudier legs.

A personal note

A note on scale. The maritime Silk Road is often treated as a smaller version of the overland trade, but in volume terms it was the larger of the two by the eleventh century. The ships of the South China Sea and the Indian Ocean carried more goods, more cheaply, than the camel caravans ever did. The overland Silk Road is the romantic version; the maritime Silk Road is the economically significant version. A reader who only knows the overland story knows the less important half.

The geography of the maritime routes

Ships and seamanship

A personal note

Further reading

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