Firmino of the Nativity was born in Amiens (France) on August 31, 1759.

He entered the Order of Discalced Carmelites and was ordained a priest. He supported a bitter struggle for the defence of the Church during the French Revolution. Expelled from the convent at the beginning of this (1790), he continued his intense apostolate in his hometown (1790-93). Forced to leave in 1793, he carried out a very active ministry in the surroundings parishes, devoid of any religious assistance. Someone despicably informed on him and he was arrested in 1794 and sent to his death on April 14 of the same year.

The diocesan process on his martyrdom took place in Amiens in the years 1928-29. The vote on his writings is dated November 27, 1937. The decree of validity was granted on October 11^th, 1991.