Saint Emmanuel Nguyen Van Trieu was born in 1756 in Kim Long village, Phu Xuan district, in what is now Thua Thien Hue province. His father, Mr. Nguyen Van Luong, was a Catholic military officer serving the Nguyen Lords, who died in battle against the Tay Son brothers. Orphaned of his father at a young age, Trieu lived with his mother in Tho Duc village and joined the army at age 15.
In 1786, the Tay Son army attacked and recaptured the capital of Phu Xuan. Trieu and the troops of Lord Trinh Khai withdrew to Thang Long. At age 30, after 15 tumultuous years in the military, Trieu resigned from the army and asked to enter religious life. Bishop Emmanuel Obelar accepted him and sent him to study at the Trung Linh Seminary.
After 6 years of study, in 1793, Trieu was ordained a priest by Bishop Feliciano Alonso. During the reign of King Canh Thinh (1792-1802), the political situation was complex as the army of Lord Nguyen Anh in Gia Dinh frequently attacked the capital Hue, with support from some French soldiers recruited by Bishop Pigneau de Behaine.
At the end of 1797, King Canh Thinh intercepted a letter from Lord Nguyen Anh to Bishop Labartette in Phu Xuan. Suspecting the Catholics were supporting the invading forces, the king issued an edict on 7/8/1797 to arrest missionaries and catechists. When searching the Men Thanh Gia church in Tho Duc, soldiers captured Father Trieu.
On the morning of 17/9/1798, officials interrogated Trieu one last time about renouncing his faith to be spared, but he refused. At 10am that day, he was taken to the Bai Dau execution grounds and beheaded. His remains were buried in Duong Son church, with a portion taken to Tho Duc parish church.
On May 27, 1900, Father Emmanuel Nguyen Van Trieu was beatified, and on June 19, 1988, he was canonized a saint.