Saint Vincent Nguyen The Diem was born in 1761 in An Do Nam village, Quang Tri province, in a family with three children. As a child, he herded buffalo. When admitted to the seminary, he learned Latin, assisted missionary Jacques Longer - Gia, studied philosophy at Ke Vinh Seminary, and was ordained as a priest in the Western Tonkin diocese.
For 30 years, Saint Diem served in the parishes of Con Nam (Dong Dung), Lu Dang, Dan Sa, and many other branch parishes in Bo Chinh district. He lived gently, diligently offering Mass daily, praying, reciting the rosary, and meditating. Despite his advanced age, he still fasted two days a week. He taught students, worked hard to convert non-believers, and sent catechists to baptize non-Christian children.
On July 27, 1838, upon hearing that Father Khoa had been arrested, Saint Diem sent someone to ask the faithful in An Bi village if they would be willing to shelter him. However, they refused, feeling the village was unsafe. While he was still in the fields near Dan Sa village, Quang Binh province, and unsure where to go, he was arrested on July 31, 1838. On the same day, missionary Borie - Cao and catechist Nguyen Khac Tu were also arrested. All three were then taken to the Dong Hoi courthouse.
At the courthouse, officials forced Saint Diem to confess. At 77 years old and out of fear, he revealed a few families who had sheltered him. When Father Cao entered the prison and said that this confession had harmed some parishioners, Saint Diem sought to correct his mistake and told the officials: "Because I am old, and hearing your threats made me afraid, I implicated many believers. Now I ask for your mercy to forgive them and let them go. As for me, I will take full responsibility."
On the morning of November 24, 1838, at the Dong Hoi execution ground, after praying, Saint Diem was strangled by soldiers. His body was initially buried in Dong Hoi, then later reburied in Huong Phuong parish.
Father Vincent Nguyen The Diem was beatified on May 27, 1900, and canonized as a saint on June 19, 1988.