Afterpassing the military service examination in his youth, John Yi Jeong-sik becamean officer in the Dongnae region. At the age of fifty-nine, he learned Catholicdoctrine and began to live a life of faith, eventually being appointed parishleader. When the Byung-in Persecution erupted in 1866, he fled with his familyand other believers but was captured. Even under torture, he clearly professedthat he was a Catholic and acknowledged that he had instructed many believers,yet he never betrayed the hiding places of those still not arrested. Beforehis execution by beheading, he prayed the prayers of the Church and made theSign of the Cross, faithfully witnessing to Christ until the moment of hisdeath.