The earliest known ancestors are Julien le Couturier and his wife Marguérite Pottier of Rennes, the capital of Brittany. They had eight children: Michel (1636), Pierre (1637), Jean (1638), Jeanne (1641), Gilles (1640), Charles (1642), Julienne (1643), and Guilaume (1644). They lived in the Toussaint parish, where all the children were baptized, and would have been familiar with the nearby market square (above).

Gilles Couturier and his wife Marie Jeanne Élisabeth Tarragon (a "fille du roi," daughter of Loup de Tarragon and Élisabeth Demerlin of Trancrainville) lived in Sorel; he was a soldier of the Carignan regiment, and was in Canada by 1665. They married in Québec, but we are not certain where or when (though we known that Élisabeth was born in 1651 and came to Canada in 1675). Their first child Pierre was born in Sorel in October 1677. Their other children were Jean-Baptiste (1679, married Jeanne Renoux) and Gilles (1681). When Élisabeth died, Gilles married Marie-Jeanne Moral, widow of Jacques Maugras. The family moved at some point to St-François du Lac, where most of the children were married.

Pierre Couturier was married in May 1705 to Marie-Gertrude Maugras (daughter of Jacques Maugras and Marie-Jeanne Moral, and therefore his step-sister). Their children: Marie-Exupère (1706, married François Chapdelaine); Marie-Anne Élisabeth (1708, married Toussaint Niquette); Marie-Charlotte (1709? married Denis Levasseur); Joseph (1712, see below); Marie-Louise (1715-1736); Marie-Jeanne (1717-1735); Marie-Jeanne (1722-1762, married Joseph Joyal, brother of our ancestor Marie-Anne, who married Jacques Martin); Pierre (1724-1726); Marguérite-Thérèse (born and died 1727); Marie (1728, married Jacques Cartier); and François (1729? married Marie-Françoise Giguère).

Joseph Couturier (born December 26, 1712 in St-François du Lac) married Marie-Louise Alard on August 28, 1741, in the same town. Known children: Marie-Louise (1742-1759); Marie-Exupère (1743-1744); Marie-Charlotte (1744, married Joachim Richtot); Joseph (1746, married Marie Lebrun); Marie-Marguérite (1748, married Bonaventure Lebrun); Marie-Madeleine (1752, married Jean-Baptiste St-Germain on August 30, 1773); Pierre (1754, married Josephte Lefort); and Michel (1758, married Marguérite Caron).

Jean-Baptiste St-Germain died within four years of the marriage, leaving two children; Marie-Madeleine then married Amable Leburn (January 1777) and had six more children.

See St-Germain for Marie-Madeleine's descendants by her first marriage. . She is a geat-great-grandmother of Joseph Arthur Martin.