Ko Seon-yang was born to a family which lived in Changmal, Sinchang, Chungcheong-do for generations. As he was a reasonable and somewhat educated man, he also assumed the duties of the village headman.
He learned the catechism when he was young, but he could not lead a life of faith devoutly because of his family’s objection. In his mid-years, he persuaded his parents and his entire family became Catholic. After that, he practiced church doctrine faithfully. He copied spiritual books by hand and distributed them to other Faithful. Unfortunately, his baptismal name is unknown.
When the Byeong-in Persecution broke out in 1866, his stepmother Protasia Paek was first arrested by the police of Cheonan and then taken to Gongju. The eldest son’s wife and third son’s wife were also arrested and taken to Gongju. His wife and youngest son were also arrested by the police in Seoul, but the later events of their lives are not recorded.
Meanwhile, Ko Seon-yang managed to evade capture for a while along with the remaining family members, but he was arrested by the police from Gongju along with his eldest and second son after somebody informed the police about him and about the spiritual books which he distributed.
After Ko Seon-yang, his eldest son, and his second son were taken to Gongju, they were dragged before the magistrate and interrogated. Once he was put in prison along with his sons, he met his stepmother Protasia Paek. She welcomed Ko Seon-yang and his sons, and encouraged them by saying, “As we all are arrested, let us die martyrs for the Lord so as to enjoy eternal happiness and comfort in heaven.”
After that, Ko Seon-yang was martyred by hanging with his stepmother Protase and his two sons in 1867. Ko Seon-yang was 64, his stepmother Protasia, 74, his eldest son was 24, and his second one 21 years of age when they were martyred. Around the time of Ko Seon-yang’s martyrdom, his three daughters-in-law were also martyred by hanging.
