What This Document Proves - THE BREAKTHROUGH EVIDENCE:

This baptism record is THE KEY DOCUMENT that definitively proves William Thornton was Owen Hamall's half-brother through their shared mother, Mary McMahon.

The Critical Evidence Chain:

1. This baptism record (c. 1856) names Mary McMahon as William Thornton's mother and Patrick Thornton as his father.
2. The 1855 marriage record shows Mary McMahon (explicitly identified as "widow of Henry Hamall") married Patrick Thornton in Montreal.
3. The 1841 marriage record shows Mary McMahon married Henry Hamall in Donaghmoyne, Ireland.
4. Owen's 1898 death certificate and sister Mary Ann's records name Henry Hamall and Mary McMahon as parents.
5. Therefore: Owen Hamall and William Thornton shared the same mother (Mary McMahon) but had different fathers (Henry Hamall vs. Patrick Thornton) = half-brothers.

Why This Document Was Essential to Solving the Mystery: For six years (2018-2024), the identity of "Thornton Hammil" in the 1880 census remained unsolved. Traditional surname searches failed because the census had recorded William under Owen's surname. The breakthrough came when:

• The 1883 baptism records showed reciprocal sponsorship between Owen and William
• This proved a close family relationship but didn't explain the different surnames
• This baptism record provided the missing link by naming Mary McMahon as mother
• The 1855 marriage record then connected Mary McMahon (widow) to Patrick Thornton
• The entire family structure suddenly became clear: blended family from maternal remarriage

What This Document Proves:

The Critical Parental Notation: The marriage record explicitly states William was "fils majeur de Patrick Thornton et de défunte Mary McMahon" — meaning "adult son of Patrick Thornton and of the deceased Mary McMahon." This single phrase provides multiple pieces of crucial evidence:

1. Confirms Patrick Thornton as father - Validates the baptism record
2. Confirms Mary McMahon as mother - The KEY connection to Owen Hamall through shared mother
3. Documents Mary's death before 1881 - The notation "défunte" (deceased) confirms Mary had died before William's marriage on August 20, 1881
4. Shows Patrick Thornton still living in 1881 - Patrick is not noted as deceased

Marriage Details: William Thornton (age 24-25, born c. 1856) married Mary Jane Lynch on August 20, 1881, in Granby, Quebec. The marriage location rather than Chicago suggests William maintained Quebec connections even after spending time in Chicago (the 1880 census showed him living with Owen).

The Tragic Future: This 1881 marriage would produce three children—none of whom would survive to adulthood. Within five years, William and Mary Jane would bury all three children in Chicago. The parallel tragedies of the two half-brothers' families—Owen lost four children 1892-1893, William lost three children by 1886—created devastating losses for both branches of Mary McMahon's family.

What This Proves:

KEY RECIPROCAL SPONSORSHIP DOCUMENT: Mary Margaret was William Thornton's daughter, and Owen Hamall served as her godfather/sponsor. This reciprocal sponsorship (Owen sponsored William's daughter Mary; William sponsored Owen's son William) provides definitive proof of the close family relationship. The mutual sponsorship pattern was typical of brothers. This baptism occurred the same year (1883) as Owen's son William's baptism, demonstrating coordinated family religious practices. Parents: William Thornton and Mary Lynch Thornton. Mary Margaret would die in 1886 at age 3, becoming the first of William's three children to die.

What This Proves:

Mary M. Thornton died July 31, 1886 at age 3 years, 2 months, 4 days. She was the first of William and Mary's children to die in the "Summer of Sorrow 1886." Her death began the parallel tragedy that would mirror Owen and Kate's losses six years later. Death certificate proves: (1) Parents: William Thornton and Mary Thornton, (2) Exact age calculation gives birth date approximately May 27, 1883 (consistent with baptism record from 1883), (3) Cause of death, (4) Residence in Chicago. Mary M. was buried August 2, 1886 at Calvary Cemetery—just two days after death and 18 days before her brother Eugene M. would die.

What This Proves:

This baptismal record documents the birth and baptism of Eugene, son of William Thornton and Mary Lynch, establishing him as Owen Hamall's nephew. Eugene's baptism at Holy Name Cathedral creates a poignant family connection—this was the same church where his uncle Owen married Kate Griffith in 1879. Eugene was one of three children born to William Thornton and Mary Lynch. The 1900 census documents that Mary Lynch had "3 children, 0 living," meaning all three children died.

Parallel Tragedies: William Thornton and Owen Hamall were half-brothers (same mother: Mary McMahon Hamall). William's family lost all three children, while Owen's family lost four of six children. Both families baptized sons named "Eugene" who died as infants. Both families experienced devastating child mortality rates.

What This Proves:

This death record transcript provides key documentation of Eugene Michael Thornton's death on August 19, 1886, at age sixteen months. Eugene died just twenty days after his sister Mary M. Thornton died (July 31, 1886). For parents William and Mary Lynch, August 1886 represented unimaginable horror—their daughter had died in late July, and before they could fully process that grief, their infant son Eugene also died. Within three weeks, they buried two children.

Age Calculation Confirms Baptism: Eugene died at age 16 months on August 19, 1886. Working backward: 16 months before August 1886 = April 1885, which perfectly aligns with his April 5, 1885 baptism. This independent verification confirms the baptism record identified the correct child.

What This Proves:

The death certificate provides comprehensive medical information:

• Death Date: August 19, 1886, 6:00 AM
• Age: 16 months
• Cause of Death: Cholera Infantum with complications
• Duration of Disease: About 2 hours and 15 minutes
• Burial Place: Calvary Cemetery

Cause of Death: Cholera Infantum: Eugene died from "Cholera Infantum" with complications—a diagnosis commonly used in the 19th century for severe infant diarrhea, vomiting, and dehydration during summer months. Before modern oral rehydration therapy and antibiotics, cholera infantum had extremely high mortality rates.

Rapid Death: The certificate states Eugene's illness lasted approximately 2 hours and 15 minutes, indicating an acute, rapidly fatal episode. For parents who had just buried their daughter Mary M. three weeks earlier, watching baby Eugene die rapidly in the early morning hours must have been traumatic beyond measure.

What This Proves:

The cemetery plot card provides critical information about the Thornton family burials:

• Plot Location: Lot 139, Block 6, Section T, Calvary Cemetery
• Plot Owner: William Thornton (purchased 7/31/86)
• First Burial: Mary M. Thornton (daughter, died 7/31/86)
• Second Burial: Eugene M. Thornton (son, died 8/20/1886)
• Third Burial: William Thornton (father, died 9/10/00)
• NOT Buried Here: Mary Lynch Thornton (survived until 1936)

The Missing Third Child: The 1900 census documents that Mary Lynch had "3 children, 0 living." The cemetery card shows only Mary M. and Eugene buried in the Thornton family plot. This means a third child existed—born, lived, and died—but is not documented in this cemetery plot.

Separate Plot from Hamalls: The Thornton family plot (Lot 139, Block 6, Section T) was completely separate from the Hamall family plot (Lot 17, Block 14, Section D). Despite William Thornton being Owen Hamall's half-brother, the two families maintained separate cemetery plots.

What This Proves:

William Thornton (age 44, laborer) lived with wife Mary and two nieces in 1900. Critical notation: "3 children, 0 living"—William lost all three of his children, mirroring Owen's tragedy. This census proves: (1) William survived to 1900 (he would die later that year in September), (2) His occupation: laborer (working-class like Owen), (3) He and Mary took in two nieces (extended family support network), (4) The notation "3 children, 0 living" confirms three children were born but all died, (5) Only two deaths documented (Mary M. 1886, Eugene M. 1886), meaning third child's death record hasn't been found. The census was taken months before William's death in September 1900.

What This Proves:

William Thornton died September 10, 1900 and was buried at Calvary Cemetery, Section T. Cemetery card notation states he died in Metropolis, Illinois—a town 360 miles south of Chicago on the Ohio River. This proves: (1) William died away from Chicago (reason unknown), (2) His body was returned to Chicago for burial, (3) He died just 2 years after Owen (Owen 1898, William 1900), (4) Age approximately 44 years old. The Metropolis death creates a mystery—why was William 360 miles from home? The cemetery burial in Chicago rather than Metropolis indicates family arranged return of body.

What This Proves:

Despite William dying in Metropolis (Massac County seat), no death certificate exists in county records. This official search result proves: (1) Reasonably exhaustive research was conducted, (2) The absence of a death certificate doesn't disprove William's death—cemetery records confirm death, (3) Late 19th/early 20th century death registration was incomplete, especially for non-residents who died while traveling, (4) The negative result demonstrates professional research methodology (document unsuccessful searches). This documented negative search meets BCG standards for establishing absence of evidence.