Having once been a military mandarin supporting Lord Nguyễn, his father died in battle during the conflict with the Tây Sơn brothers. Growing up fatherless, at the age of 15, the young man Nguyễn Văn Triệu joined the army. In 1786, when the Tây Sơn army recaptured the imperial capital of Phú Xuân, he followed the army of Lord Trịnh Khải as it withdrew to Thăng Long.
At thirty years old, after fifteen years of military service, he left the army to dedicate himself to religious life. Bishop Emmanuel Obelar accepted him into the Trung Linh Seminary. Six years later, Deacon Triệu was ordained a priest by Bishop Feliciano Alonso.
Under the reign of King Cảnh Thịnh (1792-1802), the political situation was complex. The army of Lord Nguyễn Ánh from Gia Định advanced annually to attack Huế, with the support of a number of French soldiers recruited by Bishop Pigneau de Béhain. At the end of 1797, after intercepting a letter from Lord Nguyễn Ánh sent to Bishop Labartette in Phú Xuân, the king suspected Catholics of aiding the enemy.
On August 7, 1798, a royal edict was issued to hunt down and arrest missionaries and religious leaders (đạo trưởng). During a search at the Lovers of the Holy Cross Convent (Nhà phước Mến Thánh Giá) in Thợ Đúc, Father Triệu was captured. While being led away, seeing his elderly mother weeping, he stopped to take his leave: "God has given me the honor of bearing witness for Him, please do not cry any longer, Mother. May you happily submit to God's holy will."
On the morning of September 17, 1798, during the final interrogation, the official asked: "Do you wish to abandon your role as a religious leader (đạo trưởng) and return to your village to live and work? If you agree, I will ask the king for a pardon." Father Triệu answered definitively: "No. I am a religious leader (đạo trưởng). I would rather die than give up preaching the faith."
At ten o'clock that morning, he was led to the Bãi Dâu execution ground. At high noon, Father Emmanuel Nguyễn Văn Triệu knelt down and received the sentence of beheading. Lay faithful then brought the body of this witness of the faith to be buried in the church of the Dương Sơn clan.
On July 21, 1996, the remains of the saint were brought by the Archbishop of Huế, Stêphanô Nguyễn Như Thể, to Thợ Đúc parish, his mother's homeland and also the place where he received baptism. His skull remains preserved at Dương Sơn parish church, in the Archdiocese of Huế.
Father Emmanuel Nguyễn Văn Triệu was beatified on May 27, 1900, and canonized on June 19, 1988.
The content about the saint in this post is summarized and paraphrased from the book “Hạnh Các Thánh Tử Đạo Việt Nam” - Lives of the Vietnamese Martyrs (Vietnamese Bishops’ Conference, edited by Bishop Peter Nguyễn Văn Khảm, Tôn Giáo Publishing House, 2018). This post is not a verbatim copy but a re‑presentation based on the original source.