Yi Sà Ânghun (; 1756 â April 8, 1801), also Ni-Seoung-Houn and baptized as Peter, was a Korean Catholic missionary known as one of the first Christians, missionaries and martyrs in Korea.
He was born in 1756 in Hanseong, modern day Seoul. His father was Yi Tonguk (, 1739-?), art name Soam (), 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. His mother was a sister of Yi Kahwan (ì´ê°ÂÃÂÂ; æÂÂ家砥, 1742âÂÂ1801), one of the Catholics executed with him in 1801.
Yi Sà Ânghun first came into contact with Catholicism via Yi Pyà Âk in 1779. In 1783âÂÂ4, he accompanied his father on a diplomatic mission to Beijing, China, and on the suggestion of Yi Pyà Âk contacted the Catholic priests there. He was baptised in Beijing in the spring of 1784. 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. Yi Pyà Âk then seems to have taken some time to study the books before declaring himself convinced. He then set about evangelizing those around him, including Kwà Ân Ch'à Âlsin and his younger brother Kwà Ân Ilsin. This was also the moment when he spoke of the Catholic faith to the brothers Chà Âng Yakjong, Chà Âng Yakchà Ân, and Chà Âng Yagyà Âng (who recorded the event in his epitaph myojimyeong.
It was only after Yi Pyà Âk felt fully convinced that he authorized Yi Sà Ânghun to baptise himself and the other converts to Catholicism. Early in 1785 the growing group of believers and sympathizers in Seoul moved their regular gatherings for worship from the house of Yi Pyà Âk to that belonging to another convert, Kim Beom-u, on the hill where Myeongdong Cathedral now stands. Almost immediately the authorities raided the house, suspecting it of being a gambling den, and were embarrassed on finding it full of nobles. Yi Sà Ânghun was among those named in the official report of the incident. After the death of Yi Pyà Âk later that year, Yi Sà Ânghun took over his role in the group. In the spring of 1786, as there were yet no formally ordained priests in Korea, Various leading Korean laymen, including Ch'oe Ch'anghyà Ân, Yi T'anwà Ân, began acting as "temporary clerics". In 1789, however, the Korean Catholics were informed by the bishop in Beijing, Mgr. Gouvea, that such practices were contrary to Church teachings and that they should cease. There would be no ordained priest in Korea until 1795, when the Chinese priest Zhu Wenmiao arrived, at which time the Church had grown to over 4000 members. Yi Sà Ânghun and Chà Âng Yakjong were the main leaders of the community in Seoul after the death of Yi Pyà Âk in 1786. Yi Sà Ânghun's wife was Chà Âng Yakjong's sister.
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. Yi was martyred by beheading on the 26th of the 2nd lunar month (April 8), 1801. This incident has come to be known as the Catholic Persecution of 1801. Little written material remains from this period but a collection of texts by several of the first believers, known as Manch'à Ân yugo (èÂÂå·Âéº稿), was discovered in about 1970. Manch'à Ân was the art name of Yi Sà Ânghun, whose writings occupy a major part of the book, together with texts written by Yi Pyà Âk etc. It is not known when or by whom the collection was made, and although it is sometimes claimed to be in the handwriting of Chà Âng Yagyong, this does not seem to be the case.