Guay / Castonguay discoveries

Although I haven’t added much to this site, I have been hard at work completing the second part of my family history series. Book 1 covers my Roy ancestry, while book 2 covers the Guay/Castonguay ancestry.

Thanks to many other family researchers, I have been able to uncover quite a lot about this family. So far, I have learned that Gaston Guay hailed from a village on the outskirts of Paris called Montreuil-sous-Bois, was a wine maker, and must have had some wealth. He purchased a few pieces of property when he arrived in New France, including one strategically important one called Saint-François. He was the seigneur of this land and after he died in 1682, his wife Jeanne Prévost became seigneuresse. The land eventually passed to the cousin of Jeanne, Jean-Baptiste Prévost, son of Martin Prévost.

Gaston’s eldest son, Mathieu Guay, a master stone mason of Quebec City, received a property from his father and also inherited land from his father-in-law, Vincent Poirier. He appears to have lived a good life, affording to raise 18 children in the city, many of whom survived.

Mathieu’s son Pierre, who took on the new surname Gastonguay, left the city to find land and followed his cousin Louis-Bernard Gastonguay, a missionary priest, to Saint-Roch-des-Aulnaies, on the south shore of the St. Lawrence River. This parish was part of the seigneury of Grande-Anse, owned by the wealthy family Juchereau Duchesnay. He became a farmer and with his wife, Angelique Morin, raised five children.

When Pierre was fifty years old, in 1759, the militia was called up by the governor to come defend the capital city, and so as a militiaman, Pierre Gastonguay left home and (it is believed) he took part in the battle on the Plains of Abraham, because he was listed as a prisoner of war, captured on 13 September 1759, the day of the battle, and subsequently shipped to England, presumably to Plymouth. He was never heard from again.

Pierre’s two sons, Pierre and Jean-Marie, were militiamen themselves; Pierre became captain and Jean-Marie was lieutenant and later captain. My direct ancestor Jean-Marie married twice and had in all 18 children between two wives. Through his two marriages, he formed bonds with the first two pioneering families of the seigneury: those of Jean Pelletier and Pierre de Saint-Pierre. Census records show Jean-Marie was one of the wealthiest farmers of the parish. He may have taken part in the skirmishes in 1775, the year the Americans tried to take Quebec City. He lived until 1812.

Jean-Marie’s son Jean-Charles Castonguay married into the family of Letardif. Olivier Letardif was a pioneer of New France who was friends with Samuel de Champlain, the founder of Quebec. Jean-Charles married Suzanne Tardif, the great-great-granddaughter of Olivier. She is also a descendant of Antoine Roy des Jardins, a notorious French soldier and cooper who was murdered by his landlord when he was found together with that man’s wife in bed. Antoine Roy is in no way related to my Roy ancestors from Dieppe. Jean-Charles, one of the youngest children of a family of fourteen, had no prospects for land in Grande-Anse and so with Suzanne moved to Kamouraska, a seigneury further to the east.

Jean-Charles had one surviving male heir, Charles Valentin, my great-grandfather. Charles Valentin married in Kamouraska and after the birth of his first child, moved with his wife Elisa Ouellet and child to Quebec City.

They went on to have thirteen children and Charles Valentin, who was educated, had various professions, including police man. I haven’t finished the research on this family yet, but they appear to have lived in Saint-Roch, Québec City as well as in Lévis, where he and his son Charles ran a grocery store or butcher shop.

His youngest daughter, Eva Mathilda, born in 1883, was my grandmother.



One thought on “Guay / Castonguay discoveries

  1. Monique,
    Thank you for your info.
    In comparing your info and mine I see four same ancestors. Mine are:
    Gaston Guay b. 1630 + Jeanne Prevost b. 1631
    Mathieu Guay b. 1655 + Marguerite Balan
    Pierre Guay + Angelique Morin
    Jean Marie Guay + Marie Francoise Gognon
    This wife is different but it could be a second marriage.
    These compare with your listings.
    On the trees on the surname for Gaston Guay is listed as Le Guet and the surname for Mathieu Guay is listed as Guiot. The birth dates seam to match.
    I realize the trees on FamilySearch and are public trees and subject to errors but they can give clues that need to be verified.
    My name is Mark Castonia, I live in Ashwaubenon Wisconsin which is a suburb of Green Bay. My email is It would be easier communicating directly rather than through the blog.
    Thanks again and hope to continue conversations.



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