Saint Theodora Guérin was born as Anne-Thérèse Guérin on 2 October 1798, in the village of Étables-sur-Mer in Brittany, France, to Laurent Guérin, an officer in the French Navy under Napoleon Bonaparte, and Isabelle Guérin. Anne-Thérèse was born near the end of the French Revolution.

Anne knew from an early age that she would devote her life to serving God. At the age of ten, when she was allowed to take her First Communion two years earlier than the custom of the time, she confided to the priest in Etables that she wished to enter a religious community when she was older.

Anne lost her father when she was fifteen, as he was killed by bandits. The grief proved to be too much for Isabelle Guérin, who already had lost two children, and she fell into a deep depression. The teenaged Anne accepted the responsibility of her home. At the age of twenty, she asked for her mother's blessing to join a religious order, but Isabelle was still unable to cope with her loss and refused. However, five years later, Isabelle recognized the depth of Anne's devotion to God and permitted her to leave home to join a convent.

On 18 August 1823, Anne entered the Sisters of Providence of Ruillé-sur-Loir congregation and was given the religious name of Sister Théodore.

In 1826, she began serving as a teacher and superior at the Saint Aubin parish school in Rennes. She also ministered to the needs of the area's sick and poor and received a medal for her teaching from the inspector for the Academy of Angers. While working in France, Sister Théodore became seriously ill and although she recovered, the illness damaged her digestive system. As a result, she could only eat a simple, bland diet for the rest of her life.

On 15 July 1840, Sister Théodore and five companions departed from France to sail to the United States. On 22 October 1840, Sister Théodore and her companions arrived at Saint Mary-of-the-Woods, Indiana. For several months the sisters lived in a small frontier farmhouse with the Thralls family, along with a few postulants. Sister Theodore, the foundress and superior of the Sisters of Providence of Saint Mary-of-the-Woods became known as Mother Théodore.

Mother Théodore and the Sisters of Providence opened several schools across Indiana and eastern Illinois for the Diocese of Vincennes, Indiana, as well as ministering to the needs of orphans, the sick, and the poor.

Despite their meagre resources, Mother Théodore and the Sisters of Providence of Saint Mary-of-the-Woods opened Saint Mary's Academy for young women in July 1841. In addition to establishing schools, Mother Théodore and the Sisters of Providence cooperated with Bishop John Stephen Bazin and Bishop Jacques-Maurice de Saint-Palais in the establishment of two orphanages in Vincennes, and free pharmacies at Vincennes and Saint Mary-of-the-Woods.

Her last major project was The Church of the Immaculate Conception (Saint Mary-of-the-Woods, Indiana), which was completed in 1886.

Mother Théodore suffered from poor health for most of her adult life. She died on 14 May 1856 at the motherhouse at Saint Mary-of-the-Woods, Indiana, at the age of fifty-seven.

On 15 October 2006, Pope Benedict XVI canonized Mother Théodore, and was given the official name of Saint Theodora Guérin.

Other Saints of the Day
1. Saint Adalgott
2. Saint Candidus
3. Saint Cyprian of Toulon
4. Saint Ebontius
5. Saint Maximian