Today is the feast of the Holy Korean Martyrs. Among these, the family Jeong (sometimes, especially in older works, anglicized as Chong) has a notable pride of place.
Blessed Augustinus Jeong Yak-jong was from a very highly educated Korean family -- his younger brother was Dasan, (Jeong Yak-yong), one of the greatest Korean Confucian philosophers. All the brothers seem to have come into contact with Catholic thought, although it's very difficult to determine how far any of them went (there's no proof that Dasan was ever actually baptized, for instance), and several of Bl. Augustine's brothers distanced themselves from Catholicism as the regime became increasingly unfavorable to it. Bl. Augustine became very active in the faith, however, and was widely to known to be one of the leaders in the thriving Catholic community (which was heavily driven by laity rather than priests or religious). In 1800 King Sunjo took the throne, but since he was only eleven years old, the real power was in the hands of Queen Jeongsun, his step-grandmother. She had been actively opposed for much of her life to the reforming party in the court, and she regarded Catholics as a major mainstay of that party. In 1801 she officially began persecuting Catholics (usually known as the Shinyu Persecution). The highly visible Bl. Augustine was one of the first to be rounded up. He was condemned to death and beheaded at the age of 41. Bl. Augustine's death was a reason why Dasan spent several years in exile; while certainly not Catholic by that point, if he had ever been, Bl. Augustine's brothers were now suspect to the regime. Blessed Charles Jeong Cheol-san, Bl. Augustine's son by his first wife, was arrested on the day of his father's execution, in part because he refused to give any information about the location of a priest, and was executed; he was twenty years old.
That persecution eventually passed, but several flare-ups occurred. Then in 1839, a massive persecution began (often known as the Gihye Persecution). Bl. Augustine's second wife, Saint Cecilia Yu Sosa, was put in prison, where she died. Before that happened, her son was Saint Paul Jeong Hasang was killed. He, like his father, had become a major leader in the Catholic community. He was intending to become ordained when the persecution arose and was arrested. According to the stories, he gave the judge at his trial a written defense of the Catholic faith; the judge was impressed by the defense, but pointed out that the king himself forbade the religion. St. Paul was executed at the age of 45. St. Cecilia's daughter was Saint Elizabeth Jeong Jeong-hye; she died about a month after her mother.