Father Yu heng-de(余恒德), a Chinese who volunteered for Joseon missionary work, was expected from the beginning to play the role of an assistant to help Bishop Bruguière, Vicar Apostolic of Korea(朝鮮代牧區長), enter the country. However, Father Yu did not try to stay in the position of an assistant, but as a missionary dispatched by Congregatio de Propaganda Fide(布敎省) and a priest in the Joseon mission field, he tried to find the best mission plan. After discussions with Joseon believers, he presented a plan to train Korean priests to Bishop Pires Pireira, the vicar of Nanjing Diocese(南京敎區長) and Apostolic Administrator of Beijing Diocese(北京敎區長 代理). In addition, he even mentioned the autonomy of the Korean church under the long-term perspective. On the other hand, he judged that the existence of Westerners could bring danger to the Joseon Church, and stopped the smuggling of Bishop Bruguière, Vicar Apostolic of Korea.
Father Yu"s actions were recognized as excess of authority and disobedience by Bishop Bruguière, and the ‘autonomy of the Korean Church’ that Father Yu aimed for was contrary to the policy of the Society of Foreign Missions of Paris(MEP) and the Congregatio de Propaganda Fide. In the end, Father Yu had no choice but to obey Bishop Bruguière, Vicar Apostolic of Korea, and his proposals were stopped. Father Yu was recognized by the priests of the Society of Foreign Missions of Paris(MEP) as an ‘incompetent and reckless Chinese priest’ and an ‘obstructionist’, and after Father Maubant entered the country, his pastoral activities were suspended and he had no choice but to return to China.
Father Yu"s proposal to train priests was frustrated because he could not overcome the limitations of being an East Asian priest, who was limited to an auxiliary role in the Western supremacist Perspective at the time. However, when Father Yu returned to China, three Korean seminarians accompanied him, so a Korean priest could be born. The seminary student candidates selected by Father Yu were eliminated and newly selected candidates, but Father Yu"s argument that the Korean Catholic Church could not be broken and spread Catholicism only when a Korean priest came out convinced the Joseon believers who were passive in training Korean priests.