My Pastor is in China this week and he emailed a personal account of this interesting discovery:
Digging in China - Christian History: "In about 1625 some Chinese digging the foundations of a house near Xian, China's ancient capital, chanced upon a black marble monument. The Chinese characters inscribed at the top said, 'The Monument Commemorating the Propagation of the Ta-ch'in Luminous Religion in the Middle Kingdom.' Syriac characters on the stone described the arrival of a missionary, Olopen (or Alopen), in 635. The text also named Chinese emperors who had supported this religion and listed the religion's leaders, including one bishop, 28 presbyters, and 38 others, likely monks."
Turns out that Christian Missionaries in China date back much further than Hudson Taylor.
See this link for more.