from the Pyeongchang clan, who rose to the rank of champan (vice-minister) and, after possible initial interest, fiercely opposed the spread of Catholic teachings.
In 1783–4, he accompanied his father on a diplomatic mission to Beijing, China, and on the suggestion of Yi Byeok contacted the Catholic priests there.
This was the first time that a member of the Korean yangban class was formally baptised as a Christian and he returned to Korea with books, crucifixes, and other Catholic artifacts.
Early in 1785 the growing group of believers and sympathizers in Seoul moved their regular gatherings for worship from the house of Yi Byeok to that belonging to another convert, Kim Beom-u, on the hill where Myeongdong Cathedral now stands.
In the spring of 1786, as there were yet no formally ordained priests in Korea, Various leading Korean laymen, including Choi Chang-Hyon, Yi Tan-won, began acting as "temporary clerics".
In 1801, the Korean Catholic Church was subject to the first major repression by the government (the Sinyu Persecution) in which more than 300 people were killed.