Agatha was born in Korea some time during the year 1820 to a government and his wife (who would become Saint Magdalene Han Yong-i). As was the tradition at the time, she was married at a young age but continued living with family as her new husband was too poor to care of her. When the Chinese priest Yu Pang-che Pacificus visited Korea, she begged to have her marriage annulled so that she could remain a virgin. He granted this, but unsubstantiated rumors ran wild of an inappropriate relationship between the two. When Yu Pang-che Pacificus left again for China, she was determined to make up for the trouble she had caused by offering herself as a martyr to God.
Shortly after turning 21, the great Gihae Persecution began, one of the five main waives of Catholic persecution in Korea at the time. Christians were targeted as the state believed they were upsetting the Confucian ideals. She was arrested with her mother, Saint Agatha Yi Kyong-i and a several girl but was quickly separated from her mother and placed under house arrest. An apostate offered her freedom if she left the house with him, but flat refused. Both her and the servant girl were subject to extreme torture and beaten in court. In a letter she smuggled out to a friend she wrote
"I am a believer and will remain a believer till the day I die"
One month after her mother was martyred, on January 31st, 1840, she was beheaded in Danggogae. The Korean bishops would write
"This young Korean woman offered God more tears and more fragrant perfume than Mary Magdalene of Jesus' time"
Pope John Paul II canonized her, eight of the other Danggogae martyrs and Saint Mary Yi Seong-rye, when he canonized 103 martyrs and missionaries killed during the Korean persecutions. Today, you can visit a shrine dedicated to the martyrs at Donggogae.