Yi Peter is considered one of the founders of Catholicism in Korea, and the reason he was given the baptismal name of Peter. After martyrdom his body was buried beside his two sons in Incheon. In 1981 the grave was opened, and parts of the remains were moved to Chon Jin Am, considered the birthplace of Catholicism in Korea.
Yi's father was a well-known scholar, and Yi Seung Hoon was born the first son. He was the brother-in-law of Dasan, Jeong Yak-yong an outstanding Korean philosopher and his mother was the older sister of Yi Gahwan, another scholar who died in prison.
Yi Peter began his studies to become a civil servant, passed the exams and soon met Yi Byeok from whom he learned about Catholicism. On Yi Byeok's advice, Yi Seung-hoon joined his father on the father's official mission to Peking. During the 40 days in China, he went to the Catholic church in Beijing, continued his studies, and was baptized by Fr. Louis de Grammont, a Jesuit priest.
When he returned to Korea, he brought with him religious books, crosses, rosaries and holy cards and remained absorbed in the study of Catholicism. Not long after, he baptized Yi Byeok, giving him the name John the Baptist, and together began to spread the faith among the middle class. By the year 1789, he had baptized as many as a 1,000 and notified the priests in China of what was happening in Korea. He became the leader of the first Christians here.
This history of the Catholic Church of Korea is well known, and we can see how conducive family relationships were in the early spread of the faith. Yi Byeok, in his role of John the Baptist, helped bring others to Jesus despite the objections of his father.
Below is a letter by Fr. Jean Mathew de Ventavon, sent to his friends in Europe, that relates the story of the 1784 visit of Yi Peter to China:
You will be gratified to learn of the conversion of a person whom God has perhaps raised up to spread the light of the Gospel in a kingdom where it is not known that any missionary has ever penetrated it is Korea, a peninsula located to the East of China. The king of this country sends ambassadors to the emperor of China every year, for he regards himself as his vassal. He loses nothing by it, for if he goes to considerable expense in sending him presents; the emperor gives him much, or more in return. These Korean ambassadors came they and their suit, at the end of last year, to visit our church; we gave them some religious books, The son of one of these nobles, aged 27 and a very good scholar, read them eagerly. He saw the truth in them, and grace working in his heart; he resolved to embrace the faith, as soon as he had received instructions. Before admitting him to Holy Baptism, we asked him many questions, all of which he answered satisfactorily... Finally, before his departure to return to Korea, with the consent of his father, he was admitted to Baptism, which Louis de Grammont administered to him, giving him the name of Peter. His surname is Yi. He is said to be related to the royal family. He declared that on his return, he wished to retire from public life with his family, and devote himself to his salvation. He promises to send us news every year. The ambassador also promised to propose to the king that he should summon Europeans to his lands. From Beijing to the capital of Korea is a journey of about three months. For the rest, we can communicate with the Koreans only by writing. Their writing and that of the Chinese is the same, as regards appearance and meaning, but the pronunciation is quite different. The Koreans put in writing what they want to say; on seeing the characters, we understand the meaning, and they also understand the meaning of what we write.
