Margaret O. Sheldon, formerly known as Sister Mary Frances Therese and, for a brief time during her first marriage, Peg Matheson, passed away peacefully in Baton Rouge, Louisiana, on May 13, 2026. She was born Margaret Ann O’Quinn on June 11, 1936, in Colfax, Louisiana, to James Jefferson O’Quinn III and Clothilde Inez Wells O’Quinn.
Margaret’s father died suddenly when she was just eleven years old, a loss that helped shape her strength, resilience, and deep faith. At the age of seventeen, she entered the Dominican Sisters and became Sister Mary Frances Therese. During her eighteen years in religious life, she devoted herself to education, teaching mathematics in numerous schools and ultimately serving as a principal. Her dedication to her students and her passion for learning left a lasting impact on generations of young people.
Following her years in religious life, Margaret married James Leon Matheson. During that time, she was known as Peg Matheson, the name under which she served on the St. Tammany Parish School Board while teaching at Southeast Louisiana Hospital in Mandeville, Louisiana.
On December 26, 1987, Margaret married Richard Bruce Sheldon and moved to Prescott, Arizona. There, she began a new chapter in her professional life, working for Sturm, Ruger & Company.
Margaret was gifted in many ways beyond the classroom. She lovingly created handmade quilts for her many nieces and nephews, each one carefully crafted and treasured as a lasting reminder of her love, creativity, and generosity.
A lifelong teacher at heart, Margaret rarely passed up an opportunity to educate those around her. Family and friends can easily imagine her now reminding St. Peter that “the decimal point never moves.”
Margaret was preceded in death by her parents; her husband, Richard Bruce Sheldon; her brothers, Frank Morat O’Quinn and James Jefferson O’Quinn IV; her sisters-in-law, Jackie (Frank) Guidry O’Quinn, and Janice Robyn (Ed) Jones O’Quinn; and her brother-in-law, Lenny (Fran) Robichaux.
She is survived by her brothers and sister, Edwin Boothie O’Quinn, Milton David (Theresa) O’Quinn, and Frances Corrine Robichaux; sister-in-law, Patricia (Jimmy) Ford O’Quinn, along with numerous nieces, nephews, great-nieces, and great-nephews.
Relatives and friends are invited to attend the visitation at St. Jude the Apostle Catholic Church 9150 Highland Rd, Baton Rouge, LA 70810 on Tuesday, May 19, 2026 from 9:30 a.m. until 11:00 a.m., followed by a Mass of Christian Burial in the sanctuary. Graveside services will immediately follow at Greenoaks Memorial Park.
