This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
Christianity reaches China through the Church of the East, arriving at the Tang court of Emperor Taizong in 635 CE in the person of the bishop Alopen, who was received there directly. The reception led quickly to imperial sanction: around 638 an edict authorized a monastery at the Tang capital, Chang'an, marking the earliest well documented arrival of Christianity anywhere in China.
The mission carried by Alopen and the community that followed him built congregations across northern China over the following century and a half. Their own account of that growth survives on the Xi'an Stele, a large inscribed stone the community itself erected in 781 CE, recording the mission's history and naming its congregations across the region in its own words rather than through outside report.
That stone did not survive openly. It was buried at some point, probably during a later persecution of the faith in China, and lay hidden for centuries until its rediscovery between 1623 and 1625, when it became the foundational primary source for everything now known about the mission's own history. What this changed for Christianity's spread was the opening of an entirely new frontier, carrying the faith of the Church of the East, already established in Sasanian Persia, across Central Asia to the Tang court itself, the furthest east organized Christianity had yet reached.