The pool that closed

A Catholic parish in early nineteenth-century Quebec was, demographically, a small and mostly closed system. People married within walking distance of home, generation after generation, in communities that hadn't grown much since their founding a century earlier. Do that for long enough and the family trees of everyone in the parish start running back into each other. Canon law had a mechanism for when they ran together too closely: a dispensation, granted by the bishop, permitting a marriage between relatives inside the otherwise-forbidden degree of kinship. This family's records hold five of them.

Six dispensations in seventy-seven years

1804, St-Constant. Charles Beauvais and Rose Bétourné married with a dispensation from the third to fourth degree of consanguinity, granted by the Bishop of Québec — the earliest documented instance in either line, on the Oligny side, half a century before the others. Their daughter Clotilde would go on to marry Isaac Oligny in 1821 — which puts Charles and Rose on the direct line itself. They sit off the Oligny surname, but they are ancestors of Philorum and of Joseph Philorum Oligny after him; the full descent is on Jeanne Denot’s page.

Marriage act, 17 April 1804, St-Constant, dispensation clause in the curé’s own hand, sighted · baptism of their daughter Clotilde, 24 June 1804, St-Constant, sighted · marriage act, Isaac Oligny × Clotilde Beauvais, 26 February 1821, St-Constant, naming her as daughter of Charles Beauvais and Rose Bétourné, sighted · graded Proven

1851, Montréal archdiocese. Narcisse Marceau and Lucie Oligny married as first cousins, with the archdiocese's dispensation on file — not a first instance between these two families, either: a Marceau-Oligny marriage had already taken place in 1820, one generation earlier, at l'Acadie.

1854, St-Jean-Baptiste-de-Rouville. Guillaume Saurette Jr. married Elmire Jourdain-Lafrance with a dispensation from the third to fourth degree, certified by the Bishop of Saint-Hyacinthe. This one is fully traced: both descend from Jean-Baptiste Larose-Soret and Marie-Catherine Gauthier dite Saint-Germain, married at Chambly in 1763, ninety-one years earlier — Guillaume in three generations, through their son Joseph, Elmire in four, through their other son Jean-Baptiste and then his own son of the same name. Second cousins once removed, confirmed from both directions.

Marriage act, 27 Feb 1854, St-Jean-Baptiste-de-Rouville, dispensation clause in the curé's own hand · PRDH couple #293884 · graded Proven

A fourth instance is confirmed on a sighted original: Amédée Saurette and Arzélie Marcil married on 19 January 1869 — fifteen years after the 1854 dispensation, not sixteen as the family broadsheet had it — and Arzélie's mother, Julienne Saurette, is confirmed. The act reads the consanguinity dispensation as quatrième au troisième degré — the same two degrees as the 1854 case, third and fourth, just named from the opposite side. Two dispensations of the identical degree, in one family, within fifteen years, stops looking like an anecdote and starts looking like a measurement.

Marriage act, 19 Jan 1869, St-Jean-Baptiste-de-Rouville · corrects the broadsheet's 16 Jan 1870 · graded Proven

A fifth and a sixth instance, and the two tightest of those that state a specific degree, are a father and a daughter. Julien Oligny's daughter Hazilda married Théophile Beaudin at St-Rémi on 17 January 1870, and Julien himself, widowed, married Ernestine Beaudin in the same parish on 24 December 1881. Both acts carry a dispensation from the second to third degree of consanguinity — one degree closer than the 1804, 1854, and 1869 cases, all of which sat at third-to-fourth. (The 1851 Marceau-Oligny marriage, recorded only as "first cousins" with no numeric degree stated on this page, isn't directly comparable on this measure.) This is the same Julien whose son Philorum carries the direct line forward to Joseph Philorum Oligny. Two marriages into one family within a generation, at the same degree both times.

And unlike most of the others, these two are explained end to end. The common couple is Charles Beauvais and Rose Bétourné — the 1804 couple at the head of this section. Their daughter Clotilde was Julien's mother; their daughter Marguerite married Guillaume Baudin in 1823 and was Théophile's mother and Ernestine's grandmother. Both couples were first cousins once removed. The dispensation that opens this list is the kinship that produced the last two.

Marriage act, Théophile Beaudin × Marie-Hazilda Oligny, 17 Jan 1870, St-Rémi, dispensation 2nd–3rd degree, sighted · marriage act, Julien Oligny × Ernestine Beaudin, 24 Dec 1881, St-Rémi, the same dispensation, sighted · marriage act, Guillaume Baudin × Marguerite Beauvais, 10 Feb 1823, St-Constant, naming her parents Charles Beauvais and Rose Bétourné, sighted · marriage act, Guillaume Beaudin × Julienne Gagné, 18 Jan 1848, St-Rémi, sighted · the cousin degree computed from these acts · Register 02 §3.81 · graded Proven · until September 2026 this paragraph called the 1881 marriage tighter than the 1870 one; see Corrections

Measuring it: how many names were actually in circulation

Register research on the Saurette side ran a count against the full St-Jean-Baptiste-de-Rouville marriage register, decade by decade from the 1790s to the 1900s: how many distinct surnames appear against how many marriages. A ratio near 2.0 would mean nearly every wedding brought a name new to that decade. A low ratio means the same names, over and over.

The pool is tightest in the 1810s and 1820s, then loosens steadily. Guillaume Saurette Sr. married Apolline Archambault in January 1827 — the exact decade in which 229 marriages in that parish drew on only 153 distinct surnames.

Computed from a 1969 printed marriage répertoire, ~92% OCR capture, decade by decade against the full register · graded Possible→Probable — a described pattern, not a precise statistic. Surname variants (Soret/Sorette/Saurette, Doucinet/Doussinet, and others) inflate the distinct-name count in every decade; if anything, this table understates how tight the pool actually was.

Measuring it a second way: how many ancestors are actually distinct people

The surname count above measures the parish from the outside — how many different names show up at the altar. Run the same question from the inside, against this family's own traced pedigree, and it says the same thing in a different form. Two parents, four grandparents, eight great-grandparents — the number of theoretical ancestor slots doubles every generation back, in principle without limit. In practice, in a parish this size, it stops doubling well before it should, because the same people start filling more than one slot.

Both lines are complete — full slots, no gaps — through five generations back. Then the fall-off starts, and by the ninth generation fewer than half the theoretical slots on either side hold a distinct person; the rest are filled by someone who already appears elsewhere in the tree. That curve is what a shrinking pool looks like measured from the inside, rather than counted from a marriage register: not a metaphor, the literal shape of a family repeatedly marrying back into itself.

Computed across the project's full traced pedigree — 842 ancestors on the Oligny side, 984 on the Saurette side · graded Possible→Probable as an aggregate. The fall-off is part real endogamy and part the limit of what has been traced back this far, and the two cannot be cleanly separated from this data alone.

Where the two curves actually meet: eight women

Both measurements above describe a shrinking pool in the abstract — a parish, a pedigree, a shape. What they predict, if the two 1912 spouses really did come out of the same closing pool rather than two separate ones that happened to intersect once, is that their family trees should overlap well before their own generation. They do. Eight women — four filles à marier and four filles du roi (see Filles du roi & filles à marier for what distinguishes the two waves) — are documented ancestresses of both Joseph Philorum Oligny and Marie-Anna Saurette, every one of them closed on both branches — six sighted on parish acts at every joint, two carrying a single compiled or unlocated joint that their own pages name. The full page for each woman, with her own sourcing, is at Shared Ancestors; what belongs here is what the eight of them, taken together, actually show about how a pool like this closes.

All eight closed end to end, both branches, on the split points that decide the degree of cousinship. Six descents are graded Proven at every joint: Doucinet, Gobinet, Desbordes, Ardion, Duval — and Catherine Fourrier, whose last compiled joint closed in September 2026 on two independent acts. Two are graded Probable, because a chain is only as strong as its weakest joint: Jeanne Mechin's own marriage has no located act, and Marie-Louise Lecoutre's own marriage to Nicolas Crevier is unsighted. None of these sit at a split point, so none change a count in this table — but they cap the grade, and each is visible on the ancestress's own page. Full sourcing at Shared Ancestors.

Three things about this table are worth naming rather than leaving as eight isolated coincidences. Most of the eight split through daughters. Marguerite Ardion and Marie-Louise Lecoutre, for instance, are both grandmothers — one paternal, one maternal — of the same pair of Baudet sisters, one sister's line running to Oligny, the other's to Saurette; Marguerite Doucinet does the same through her own daughters one generation down. One splits through two sons instead — Jeanne Mechin, the only one of the eight whose split between the 1912 couple runs through brothers rather than sisters, Pierre and Jean Pepin, one of whom stood witness at the other's wedding in 1681. Finding her cost the most work of the eight: the Saurette-side surname changes twice on the way down, Pepin to Lanouay to Cazarant dit Ladebauche to Cazarans to Casavant, the same family under five names in five generations (see Dit Names). And one reaches further than the other seven. Mathurine Desbordes is an ancestress not only of Joseph Philorum and Marie-Anna, but of Gideon Rock — the man Marie-Anna married after her first marriage ended — making both of her husbands her cousins, on two entirely separate lines, and turning what looks on this table like a pair into what the rest of the site calls the convergence a second time over.

Why the pool was shrinking

Part of why the pool stayed small is grimmer than arithmetic. Guillaume Sr. lost two wives to childbirth within twenty-six months of each other — Apolline Archambault twenty-one days after bearing twins, Zoé Halde fifteen days after her own delivery. Every death like that removed a woman of marrying age from the pool and, often, sent a widower back into the same small set of families to remarry. The endogamy and the mortality aren't two separate threads. One fed the other.

None of this reads, on the page, as anyone's private failing. A dispensation clause is a bishop doing his job, not a parish confessing to something. Run three different measurements — a marriage register, a pedigree chart, and eight women's own descent lines — and they agree with each other before they agree with any theory: a rural Catholic parish, a century after its founding, had simply run out of room to marry a stranger.