Christianity has been present in China since the early medieval period, and became a significant presence in the country during the early modern era. The Assyrian Church of the East appeared in China in the 7th century, during the Tang dynasty. Catholicism was one of the religions patronized by the emperors of the Mongol-led Yuan dynasty, but it did not take root in China until its reintroduction by the Jesuits during the 16th century. Beginning in the early 19th century, Protestant missions in China attracted small but influential followings, and independent Chinese churches were also established.

Emperor Wuzong of Tang, né Li Chan, later changed to Li Yan just before his death, was an emperor of the Tang dynasty of China, reigning from 840 to 846. Emperor Wuzong is mainly known in modern times for the religious persecution that occurred during his reign. However, he was also known for his successful reactions against incursions by remnants of the Uyghur Khanate and the rebellion by Liu Zhen, as well as his deep trust and support for chancellor Li Deyu.