Buddhism travels east

The most consequential cargo of the Silk Roads weighed nothing. Buddhism, born in northern India around the fifth century BC, reached China by the first century AD, carried by merchants and monks from Central Asia. Chinese sources mention a prince supporting Buddhist monks as early as AD 65. Over the next five centuries Buddhism became one of China's great religions, and from China it spread to Korea and Japan.

The first problem was language. Indian Buddhist texts were written in Sanskrit and related languages, full of ideas such as karma, rebirth and emptiness that had no Chinese equivalents. Early translators borrowed familiar words from Daoism, a method later called geyi, explaining Buddhist ideas with Daoist terms, or "matching the meanings". It made Buddhism easier to grasp but also blurred it, and later scholars criticized the practice for making a foreign teaching sound too much like a native one.

Translators and pilgrims

Better translations came from people who lived in both worlds. Kumarajiva (about 344 to 413) was a monk from Kucha who translated scriptures in Chang'an. Born to an Indian father and a Kuchean princess, he was carried off to China by a conquering army and later brought to the capital in 401, where he led a team that produced elegant Chinese versions of texts such as the Lotus Sutra, still widely read.

Traffic ran both ways. Chinese monks walked west to find authentic texts at their source. Faxian set out in 399 and returned by sea in 412. The most famous pilgrim, Xuanzang, left in 629, at a time when the Tang court had forbidden travel beyond the frontier. He left anyway, slipping past the border posts at night, crossed the desert nearly dying of thirst, studied for years in India and returned in 645 with hundreds of texts. This time the emperor welcomed him. His account of the lands he passed through, completed in 646, remains a vital source for Central Asia and India.

Mani's universal faith

Some religions were designed to travel. Mani, born in Mesopotamia in 216, taught a dualist faith in which the world was a battleground between light and darkness. He presented himself as the completion of earlier prophets' teachings: the Buddha, Zoroaster and Jesus had each brought part of the truth, and he brought the final revelation. His followers translated his writings freely into local idioms, so that Manichaeism looked Christian in the west and Buddhist in the east.

Mani was executed by the Persian king around 276, and his religion was persecuted almost everywhere. Yet Sogdian merchants carried it east, and in 762 or 763 the ruler of the Uyghurs, a Turkic people who then dominated the steppe north of China, converted. The Uyghur khaganate made Manichaeism its official religion, the only major state ever to do so.

Christians, Zoroastrians and Muslims

The Church of the East, a branch of Christianity centered in Mesopotamia and using Syriac as its church language, also spread along the trade routes. A monk named Alopen reached Chang'an in 635 and was welcomed by the Tang emperor. In 781 the community set up the Xi'an Stele, a monument to Christianity in Chinese and Syriac. Its Chinese text describes Christian teaching with Buddhist and Daoist vocabulary, much as early Buddhists had used Daoist words, and it lists clergy with Syriac names beside Chinese ones.

Many Sogdians practiced their own form of Zoroastrianism, with fire temples in Chinese cities. After Arab armies conquered Central Asia in the eighth century, Islam spread gradually, and by the tenth century Turkic rulers in Kashgar had converted. Islam would become the main faith of the region.

Tolerance and its limits

Cosmopolitan does not mean safe. Between 842 and 845, during the Huichang persecution, the Tang state shut monasteries and banned foreign religions. Hundreds of thousands of monks and nuns were returned to lay life, and Manichaeans, Christians and Zoroastrians suffered too. In modern times, religious art along the routes has also faced attack. The giant Buddhas of Bamiyan in Afghanistan, carved in the sixth century, were deliberately blown up by the Taliban in March 2001, an act condemned worldwide as an assault on shared human heritage.

Worked example: reading the Xi'an Stele

Imagine you are a Tang scholar in 781 reading the stele's Chinese text. You meet a teaching called the "luminous religion", a sacred being described in words you know from Buddhist and Daoist writing, and praise for the Tang emperors who allowed it. Nothing on the surface tells you this is a faith from Mesopotamia. Now imagine you are a Syriac speaking priest reading the side panels. You see the names of bishops and monks in your own script, linking this community to a patriarch far to the west.

The stele was addressed to two audiences at once. To Chinese readers it says, "We are respectable, loyal and compatible with what you already value." To fellow Christians it says, "We belong to the wider church." This double message is how most faiths crossed the Silk Roads. They adapted their vocabulary to new hearers, sometimes so far that critics at home worried the message had changed, and they survived as long as rulers tolerated them. When that tolerance ended, as in the 840s, communities could vanish. The freedom to believe was not a right anyone recognized; it was a favor rulers could withdraw.