French man of letters, diplomat and artist, born in Montreal, New France, to André Grasset de Saint-Sauveur (1724–1794) and businesswoman Marie-Joseph Quesnel Fonblanche (b. 1733), he was the brother of Blessed André Grasset de Saint – Savior. He came to study in Paris in 1764 with the Jesuits of Sainte-Barbe, then began to follow the diplomatic career of his father and brother. Having worked for ten years as vice-consul on the commission under his father, he became vice-consul in Hungary, and then in Cairo. He then turned to letters and published, between 1784 and 1812, over twenty books.