The Catherine Lemesle Case Study
The Research Question
While building the Guilbault family tree, an unusual pattern emerged: the same woman—Catherine Lemesle, a Fille du Roi who arrived in Quebec in 1671—appeared in two separate branches of the family. Not two women with similar names. The exact same person, documented by the same baptism record, the same marriage contract, the same parish register entries.
This case study examines how Catherine Lemesle became an 8th great-grandmother twice over, what this phenomenon (called "pedigree collapse") reveals about colonial Quebec society, and how documentary evidence proves the connection through both family lines.
Key Finding
Catherine Lemesle's descendants through two different children—Marie Anne Morin (born 1673) and Joseph Morin (born 1682)—eventually married each other in 1757, reuniting family lines that had been separate for 85 years. Their son Gabriel Guilbault inherited Catherine's genetic legacy through both parents.
The Double Ancestry: How It Works
In standard genealogy, each generation back doubles the number of ancestors: 2 parents, 4 grandparents, 8 great-grandparents, and so on. By the 8th great-grandparent level, you theoretically have 1,024 ancestors in that single generation.
But populations were never that large in any single region. The math only works if some of those "ancestor slots" are filled by the same people appearing multiple times. This phenomenon—called pedigree collapse—was especially common in colonial Quebec, where small communities meant limited marriage choices and frequent intermarriage between families.
Catherine Lemesle & Pierre Morin
Married June 13, 1672 • Notre-Dame-de-QuébecPATH 1: Through Marie Anne Morin
- Marie Anne Morin (1673-1743)
married Guillaume Deguise, 1691 - Marie Catherine Deguise (1704-1731)
married Charles Guilbault - Charles Gabriel Guilbault (1731-1784)
married Marie Charlotte Morin, 1757
PATH 2: Through Joseph Morin
- Joseph Morin (1682-1735)
married Marie-Anne Brideau, 1704 - Joseph Morin II (1709-1781)
married M.C. Charles Croquelois - Marie Charlotte Morin (1738-1767)
married Charles Gabriel Guilbault, 1757
The Convergence (1757): When Charles Gabriel Guilbault married Marie Charlotte Morin, both were great-great-grandchildren of Catherine Lemesle—through different children. Their son Gabriel Guilbault "le voyageur" carried Catherine's heritage through both parents.
The marriage of Charles Gabriel Guilbault and Marie Charlotte Morin in 1757 was not unusual for its time—cousins marrying was common in colonial Quebec. What makes it significant for genealogical research is that it demonstrates how carefully we must trace each line, and how a single 17th-century woman's choices rippled forward through multiple branches of the same family tree.
Documentary Evidence: Catherine's Origins
Catherine Lemesle was baptized on April 16, 1646, in the parish of Saint-Pierre-du-Châtel in Rouen, one of France's largest and most prosperous cities. The parish register entry establishes her parentage clearly:
"Le 16e jour d'avril 1646 fut baptisée Catherine fille d'honorables hommes Jean Le Mesle... et Marguerite Renard son père et mère..."
— Parish Register of St-Pierre-du-Châtel, Rouen, April 16, 1646Her father, Jean Lemesle, was described as a marchand bourgeois (merchant bourgeois), indicating comfortable middle-class status. Her godfather was "honorable homme" Jacques de La Fosse, a captain of the city, and her godmother was "Damoiselle Catherine Moutrot"—both markers of respectable social standing.
Catherine's Siblings
The Fichier Origine database records that Catherine had at least one brother and one sister, both baptized at St-Pierre-du-Châtel in Rouen:
- Jacques Lemesle — baptized February 1, 1654
- A sister (name not recorded in the Fichier entry)
By 1671, both of Catherine's parents had died. The records describe her as "fille de défunt Jean Lemesle"—daughter of the late Jean Lemesle. As an orphaned single woman with some inheritance but no family protection, her options in France were limited.
The Church Where She Was Baptized
The Église Saint-Pierre-du-Châtel still stands in Rouen today, though now in ruins. The Gothic church, where Catherine was baptized in 1646, survived until it was heavily damaged during World War II. The remaining walls and tower are preserved as a historic monument.
The Voyage: Le Prince Maurice, 1671
In the summer of 1671, Catherine Lemesle boarded Le Prince Maurice at Dieppe, bound for Quebec. She was one of 86 Filles du Roi aboard that vessel, chaperoned by Madame Anne Gasnier Bourdon, the widow appointed by Intendant Jean Talon to oversee the King's Daughters program.
The ship arrived in Quebec on July 30, 1671. Catherine carried a dowry of 200 livres, of which 50 livres came directly from King Louis XIV—a standard royal supplement that made her an attractive prospect for marriage.
At approximately 25 years old, Catherine was older than many of her fellow passengers, most of whom were between 16 and 25. The journey across the Atlantic typically took six to eight weeks. Within eleven months of arrival, she would be married.
Marriage to Pierre Morin: June 1672
Pierre Morin was a former soldier in the Carignan-Salières Regiment, the famous military force sent to New France in 1665 to fight the Iroquois. He served in the Compagnie de Naurois. Born around 1648 in Saint-Étienne-de-Brillouet in western France (diocese of Luçon, Vendée), he was the son of Jacques Morin and Hilaire Guéry.
Two documents establish their marriage: a notarial contract dated June 4, 1672, and the parish marriage record dated June 13, 1672.
The Marriage Contract
The contract before notary Gilles Rageot lists witnesses of considerable standing, including Dame Anne Gasnier (Madame Bourdon herself, who had chaperoned Catherine's voyage) and Jean de Bonamour, doctor of medicine. The presence of such witnesses suggests both parties had some social standing.
The Church Marriage
The parish register entry from Notre-Dame-de-Québec identifies both parties fully. Pierre is described as "fils de défunt Jacques Morin habitant de la petite rivière" from St-Étienne-de-Brillouet. Catherine is "fille de défunt Jean Le Mesle et de Marguerite Renard" from St-Pierre-du-Châtel, Rouen.
"Le troisième jour du mois de juin de l'année mil six cents soixante et douze après les fiançailles et la publication faite des trois bans de mariage... d'entre Pierre Morin... et Catherine le Mesle fille de défunt Jean le Mesle et de Marguerite Renard ses père et mère de la paroisse de St Pierre du Châtel archevêché de Rouen..."
— Notre-Dame-de-Québec Parish Register, June 13, 1672
Research Note
Catherine Lemesle was unable to sign her name—noted in the marriage contract as having "declared not to know how to write or sign." This was common among women of her era; literacy rates were very low even in merchant families. The inability to sign does not indicate low social status.
The Morin Family: Eight Children, Two Ancestral Lines
Pierre and Catherine settled in the Petite-Rivière area of Quebec City. Over eighteen years, they had eight children. Five survived to adulthood. Of these, two are direct ancestors—but through separate paths that would not converge for 85 years.
| Child | Born | Died | Marriage / Notes |
|---|---|---|---|
| Marie Anne ★ PATH 1 | July 22, 1673 | Nov 24, 1743 | Guillaume Deguise dit Flamand, 1691 |
| Jean | Jan 28, 1676 | Aug 5, 1687 | Died age 11 |
| Pierre | c. 1677 | — | Listed on 1681 census, La Petite Auvergne |
| Louise Anne | Oct 25, 1678 | Feb 20, 1710 | Jacques Payant dit Saintonge, 1699 |
| Joseph ★ PATH 2 | Jan 5, 1682 | Dec 11, 1735 | 1. Marie-Anne Brideau, 1704 2. Dorothée Girard, 1724 |
| Marie Jeanne | April 22, 1685 | Nov 26, 1755 | Jean Baptiste Legris dit Lépine, 1711 |
| Marie-Madeleine | Jan 17, 1687 | Jan 3, 1689 | Died age 2 |
| Pierre | Oct 17, 1690 | Jan 25, 1747 | Marie-Louise Bezeau, 1721 |
The highlighted rows show the two children through whom Catherine Lemesle becomes a double ancestor. Their descendants grew up separately, married into different families, lived in different parishes—and then, in 1757, two of those descendants married each other.
Pierre Morin died December 12, 1706, and was buried at the Hôtel-Dieu de Québec. Catherine Lemesle survived him by at least fifteen years—she is last documented on June 8, 1721, in a notarial record (notary Dubreuil).
Documentary Evidence: The Two Ancestral Lines
The baptism records of Marie Anne and Joseph Morin are the starting points for tracing the two paths that would eventually reunite.
Marie Anne Morin (1673) — Path 1
Marie Anne was the firstborn, baptized July 22, 1673. She married Guillaume Deguise dit Flamand on August 12, 1691. Their daughter Marie Catherine Antoinette Deguise married Charles Guilbault, and their son Charles Gabriel Guilbault (subject of Guilbault Line Episode 4) would marry his distant cousin Marie Charlotte Morin in 1757.
Joseph Morin (1682) — Path 2
Joseph was baptized January 6, 1682. He married twice—first Marie-Anne Brideau on November 4, 1704, then Dorothée Girard on February 2, 1724. His son Joseph Morin II married Marie Charlotte Charles Croquelois, and their daughter Marie Charlotte Morin would marry Charles Gabriel Guilbault—her distant cousin through their shared ancestor Catherine Lemesle.
The 1757 Convergence
On September 26, 1757, at Notre-Dame Cathedral in Montreal, Charles Gabriel Guilbault married Marie Charlotte Morin. He was twenty-six; she was nineteen. A notarial marriage contract preceded their church wedding.
Neither may have known they shared a common ancestor. But when they married, they reunited family lines that had been separate since Catherine Lemesle's children were born in the 1670s and 1680s.
Their son Gabriel—the voyageur who would later marry an Ojibwe woman named Marie Josephte Abitakijikokwe—inherited Catherine Lemesle's genetic legacy through both his father and his mother.
Connection to The Guilbault Line
This case study connects directly to Episode 4: Charles Gabriel Guilbault — The Quebec Patriarch in The Guilbault Line documentary biography series. Charles Gabriel is Catherine Lemesle's great-great-grandson through Path 1, and he married Catherine's great-great-granddaughter through Path 2.
Continue the Story
Episode 4 of The Guilbault Line tells the full story of Charles Gabriel Guilbault (1731-1784), including his two marriages and the four sons who survived to adulthood—one of whom became the voyageur Gabriel Guilbault.
Read Episode 4 →The Guilbault Line series traces seven generations from Pierre Guilbault (arrived Quebec c. 1647) to Evangeliste Guilbault (1845-1883). Catherine Lemesle enters the story through marriage—twice—demonstrating how the maternal lines that feed into a patrilineal surname can create unexpected connections.
Research Database Records
Multiple genealogical databases confirm Catherine Lemesle's origins and family structure. The Fichier Origine documents her French baptism and family connections, while the PRDH (Programme de recherche en démographie historique) at the Université de Montréal tracks her Quebec family.
Research Significance
Catherine Lemesle's double appearance in one family tree illustrates several important principles for genealogical research:
1. Pedigree Collapse Is Common
In colonial Quebec, with its small population and limited marriage pools, pedigree collapse was inevitable. Researchers working with French-Canadian ancestry should expect to find the same ancestors appearing multiple times, especially among the founding generation of Filles du Roi and early settlers.
2. Maternal Lines Matter
While surname-based research naturally follows patrilineal descent, the maternal lines that feed into each generation often create unexpected connections. Catherine Lemesle never bore the Guilbault surname, but she appears in the Guilbault family tree through two separate marriages across two centuries.
3. DNA Implications
When you descend from the same ancestor through two lines, you potentially inherit their DNA twice—through two separate paths of transmission. This can cause DNA matches who also descend from that ancestor to share more DNA than expected for the apparent relationship level.
For DNA Researchers
At the 8th great-grandparent level, you theoretically inherit about 0.1% of your DNA from each ancestor. When descending through two lines, your expected inheritance roughly doubles. However, DNA inheritance is random—you might inherit more or less, and there's even a chance of inheriting zero DNA from a specific distant ancestor through any given path.
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