Delia Tetreault was born on February 4, 1865 with a healthy twin brother in Marieville, Quebec, Canada. Her parents, Alexis Tetreault and Celina Ponton had nine children, two of whom died at an early age. After the death of Delia’s mother in 1867, her uncle and aunt Mr. & Mrs. Jean Alix adopted her. Although she had a fragile health, she was able to pursue her studies with the Sisters of the Presentation of Mary at Marieville.

During her adolescence she showed signs of her missionary vocation. She recalled her concern for the poor and the underprivileged, the destitute and those without faith in God. She described her dream of the field of golden wheat, which turned into the heads of children of different races. This prophetic dream guided her life. At an early age she nourished an aspiration that one day she would lay the foundation of a missionary institute.

As a young woman, she devoted her time as a volunteer worker at Bethany serving the poor in the area especially the immigrants. This commitment to the poor paved the way for the Foundation of the Missionary Institute. Hence, in spite of the problems, which Delia had to put up with, the Archbishop of Montreal approved the foundation of the Missionary Sisters of the Immaculate Conception (MIC) on June 3, 1902. On November 30, 1904, Pope Pius X approved of the foundation and on December 7, 1904, the name Society of the Missionary Sisters of the Immaculate Conception (MIC) was given to the Institute, by Pope Pius X.
Starting with three members, the Society increased in number through the years.