Katherine Lheuwillier, later their name was changed to Willier, was born in Peoria, Illinois on May 12, 1869. Her father was French, her mother Irish. Her forbears were pioneer builders of the Wabash Railroad from St. Louis to Omaha. 

Katherine entered the Clyde convent on October 5, 1884, at the age of 15, was invested with the Benedictine habit on February 10, 1885, and professed as Sister M. Teresa on February 10, 1886. Perpetual vows were made on November 11, 1891, and Consecration of Virgins on November 16, 1952.

Sister was a small person, joyous, outgoing, and very charitable—always ready to lend a helping hand. In the early years she went about with a companion Sister soliciting financial aid for the struggling community, and was especially successful in obtaining funds for building the adoration chapel at Clyde. Her winsome personality gained many lasting friends for the community.

As a pioneer member of the Congregation, Sister was very faithful in helping to maintain unceasing adoration of the Blessed Sacrament. Her favorite hour for many years was from 4:00 to 5:00 a.m. From June, 1920 till March, 1928 she was at the Chewelah convent, and in 1941 spend a few months in Tucson.

Gifted with a diversity of talents, Sister served the community in various employments. Cook, baker, seamstress, organist, artist—she taught music at the Academy and was prefectress for a time. She could paint pictures as well as do beautiful embroidery and needlework. She loved to sew for poor children, for whom she literally made dozens of dresses, which she delighted to give to Mother each year on her Name Day for distribution. She wrote beautiful letters for the correspondence department; had a strong musical voice and used it joyously and zealously in praying and singing. Sister was most helpful to the many students for the Priesthood who worked and boarded at Clyde, among them the Malone brothers.

Dr. Willier, her brother, who lived in San Diego, did much for our Sisters. His wife and daughter were also very good to the Sisters. Sister M. Teresa was very proud of her nephew, Father Edwin O'Hara, who became a missionary priest in China and was ever ready to bring sacrifices and solicit interest in his work from her many friends.

In addition to her great love for the Blessed Sacrament, Sister had a tender devotion to our Blessed Mother and to the Rosary. Even in her last illness, in times of great suffering, she clasped her rosary so tightly that one could not take it from her. To the end of her life she loved to sing the hymn, "Hail, Queen and Mother Sweet," and when still able would play organ accompaniment. She also had a great love for the Sacred Heart of Jesus.

Shortly before the feast of the Assumption in 1955, Sister had a serious heart attack and from then on suffered much, until her death on August 25th, at the age of eighty-six. Her last conscious word was the holy Name of JESUS.