The Great Byzantine Silk Heist

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Silk has been a highly sought-after luxury good ever since it was first created in ancient China, as early as the 3rd Millennium BC. It was widely worn by the Chinese elite and even used as a substitute for the copper coins that were the currency of the time – an indication of its value. As foreign empires began to admire silk’s qualities too, China had a lucrative export and an international monopoly; it took two enterprising Byzantine monks to bring the secrets of silk production to the western world.

By the 2nd Century BC, the expansion of Han Dynasty China into the Tarim Basin of Central Asia opened new trade routes to the West, enabling Chinese silk to reach the markets of Parthia (Persia) and Rome for the first time. Thus, the fabled ‘Silk Road’ emerged, which enabled indirect cultural and economic exchange between East and West. For the West, the most important aspect of this was silk: such was its importance that China itself was known to the Romans as Serica, literally meaning ‘land of silk’. The demand was so great that silk was almost worth its weight in gold.

For the next several centuries, successive Chinese dynasties protected the secret to the production of silk (sericulture) and criminalised the transport of silkworms out of the country. This was done to maintain China’s monopoly over the international silk trade and to guard the immense revenue that it brought in. Despite these efforts, knowledge of the production process had spread to India by the 2nd Century AD and to Japan by the 3rd. However, the secret to the production of silk remained very much unknown in Europe.

At the same time as sericulture was spreading to Japan, Europe was experiencing immense social and political change. After the Crisis of the Third Century, the longstanding Roman Empire had split into separate eastern and western political divisions, which ultimately evolved into two entirely separate empires. The Western Empire fell to invasions from Germanic Gothic peoples in the late 400s, whilst the Eastern Empire, with its capital at Constantinople, persisted, becoming what is today referred to as the Byzantine Empire.

In AD 527, Justinian I became Byzantine Emperor. Across his momentous 40-year reign, Justinian commissioned great cultural works, notably the Hagia Sophia, survived rebellions and outbreaks of the black death, and led the empire to its greatest territorial extent. His renowned general Belisarius even led a reconquest of former Roman provinces, including Italy, North Africa, Spain and even Rome itself. However, Justinian is also remembered today as the emperor who brought the secret of silk to the Western world.

At the start of Justinian’s reign, demand for silk was rising both domestically and in the Gothic kingdoms of Europe to their west which purchased their silk from the Byzantines. This rising demand strained the already limited supply. The immense 4000-mile distance between Europe and China took upwards of 230 days to cover by caravan and crossed many notoriously inhospitable regions, such as the Gobi Desert and the mountain passes of the Himalayas and Pamirs. Many land routes were plagued by bands of brigands and criminals, whilst the sea routes were notoriously affected by pirates.

The great cost of transporting silk across this distance was compounded by the number of middlemen between China and Constantinople, all of whom took their own cut. In particular, the Persian Sassanid Empire proved to be an especially problematic obstacle. Since most land routes passed through Persian-controlled Mesopotamia and most sea routes terminated at Sassanid ports in the Persian Gulf, the Persians controlled the silk flowing into Constantinople. Under the Kings Kavad and Khosrow the Sassanid Empire was often at war with the Byzantines, and during these times of conflict silk supplies would be suspended. This made the price of silk even more volatile.

Justinian attempted to solve the problem of Sassanid interference by investing in the creation of new trade routes which bypassed Persia. One new route passed north of the Caspian Sea and along the Eurasian Steppe to China, whilst another bypassed the Persian Gulf by sailing along the Red Sea to the Ethiopian kingdom of Axum, using the less adversarial Axumites as middlemen instead. However, these routes were used infrequently enough that the Sassanids continued to control the majority of silk flowing into Europe.

From 541 – 562, the Byzantine and Sassanid empires were once again at war over the region of Lazica to the east of the Black Sea. In the midst of this conflict in 552, Justinian was approached by two monks returning from a trip to India where they had been preaching Christianity. The contemporary historian Procopius of Caesarea records how: “certain monks […] learning that the Emperor Justinian entertained the desire that the Romans should no longer purchase their silk from the Persians, came before the emperor […] for they had, they said, spent a long time in the country situated north of the numerous nations of India – a country called Serinda – and there they had learned accurately by what means it was possible for silk to be produced.” These monks were likely members of the Nestorian Church, or ‘Church of the East’, an early branch of eastern Christianity. In the 6th Century, the Nestorian Church was spreading into India, Central Asia and China (the ancient Chinese capital Chang’an had a Nestorian temple by the end of the century), which explains the presence of Byzantine monks there. Justinian promised them great rewards if they could smuggle silkworms back into Constantinople. With that, they set out on their journey.

It is believed that the monks took the northern route, passing first along the southern shore of the Black Sea, then up through the Caucasus mountains, travelling along the northern shore of the Caspian Sea (bypassing Persia), and moving along the Eurasian steppe to China from there.

China in this period was undergoing a period of disunity known as the Northern and Southern Dynasties. The multiple short-lived governments were not as strong as the preceding Han Dynasty, meaning security, both within and at their borders, was laxer. The monks did not mention any great difficulty in acquiring silkworm eggs and were supposedly able to smuggle them out in the hollows of their bamboo canes.

Upon their return, the silkworms were used to start a new domestic silk industry. The mulberry bushes required to feed the silkworms were either already imported to Constantinople by the time the monks arrived or were smuggled out of China by the monks alongside the silkworms. Either way, the descendants of the stolen silkworms were used to stock the supplies of new silk factories in Thrace (Constantinople), Greece (Thebes, Morea), Lebanon (Beirut, Tyre) and modern-day Turkey (Antioch). Traces of the Byzantine silk industry have survived to this day in some regions of Greece and Turkey.

Whilst Chinese silk continued to be of superior quality, the nascent Byzantine silk industry provided a new, more reliable source of silk from that point onwards. By removing the need to transport the silk 4000 miles across some of the most inhospitable territory on Earth, it greatly reduced the cost and made the product more accessible to the masses. Most importantly, however, the smuggling of silkworms back to the Byzantine Empire permanently ended the Chinese and Persian monopolies which had dominated the flow of this luxury good into Europe since ancient times.

Procopius, trans. Dewing, H.B., 1928. History of the Wars, Volume V. Loeb Classical Library.