In 1850 he returned to his homeland and went to preach many places before taking holy orders one after another. The bishop saw that he deserved it, so he gave him the priesthood on February 7, 1857.
He then received the superior position of Thi Nghe Seminary, in the midst of the fierce prohibition of Tu Duc King. Shortly after he temporarily sent the seminarians back to his family and he himself had to seek shelter to easily help the priesthood and seminarians. But then he was arrested at the end of December 1858 and imprisoned. In the prison, he always exemplified the faith of a pastor. He was condemned by the authorities and the court approved.
He stood out on the royal dynasty on February 13, 1859. Pope Pius X enthroned him on the Blessed Day on May 2, 1909, and Pope John Paul conferred the title of Saints on June 19, 1988.
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