Mary Yi Yon-hui was the wife of the martyr Damian Nam. Mary had a strong will and was a very intelligent woman. Like Barbara Kwon, she used to welcome Bishop Imbert and the missionaries into her home, a very dangerous act at that time, and provide them with accommodation. When the people gathered in her home, she used to take care of them, teaching them and preparing them to receive the sacraments. Her gracefulness and modesty pleased everyone around her.
Mary was 36 years old when she was arrested in 1839. She was tormented by the policemen in prison. When she scolded them for their ungentlemanly conduct, her husband Damian advised her that a Catholic should die like a tame lamb. After that she endured all abuse and cruelty with no complaints.
Her 12-year old son was in a separate prison cell. The prison guards used to torture him so that Mary could hear her son's screams. The prison guards used to tell Mary how the boy was tortured. She was afraid that her son might be overcome by the tortures and give up his faith. She tried to calm herself down, reassuring herself that all the trials were for the greater glory for God. One of the witnesses testified that she loved God from the bottom of her heart and that the only thing she wanted was Heaven. She was severely beaten and twisted.
Mary was beheaded outside the Small West Gate on September 3, 1839, with five other Catholics. She was 36 years old when she died for the faith.