James Yun Yu-o ( ? - 1801)

James Yun Yu-o was born in Jeomdeul, Yeoju, Gyeonggi-do (now, Geumsa-ri, Geumsa-myeon, Yeoju-gun, Gyeonggi-do). He moved to Hangamgae, Yanggeun (now, Daeseok-ri, Gangsang-myeon, Yangpyeong-gun, Gyeonggi-do), a nearby village. Paul Yun Yu-il, who was a secret envoy of the Church and died a martyr in 1795, was his elder brother.

James Yun learned the catechism at an early age, from his elder brother Paul Yun and became a Catholic. He was devout and dedicated himself to proclaiming the Catholic teaching to his neighbors. Furthermore, when his brother Paul Yun was martyred, he tried to encourage the faithful and helped them to strengthen their faith life by organizing prayer meetings and studying the Catholic doctrine with Justin Jo Dong-seom and Sebastian Kwon Sang-mun. In 1795, when Father James Zhou Wen-mo went on a pastoral visit to Yanggeun, he received the Sacraments from him.

When the Shinyu Persecution broke out in 1801, Catholics everywhere were arrested and martyred. James Yun was arrested by the police of Yanggeun and was taken to the government office. There he underwent severe interrogation and torture to force him to renounce his faith in God, but he remained steadfast.
The following is an excerpt from his final confession:

“I understand that the Ten Commandments, that my elder brother taught me, are the proper obligations that anybody must observe. Therefore, I read and studied the teaching day and night. Truly I have not the slightest intention to apostatize."

The magistrate, on realizing that he would not change his mind, sentenced him to death. On April 27, 1801 (March 15, by the Lunar calendar), he was taken to the wide street located in the westside of the city. He was beheaded and died a martyr with his companions.