Saint Louis-Marie Grignion de Monfort was born in 1673 in France. He was ordained in 1700. He also became a third order Dominican that year. He had a particular devotion to Mary and is one of the early writers in the area of Mariology and on Marian devotion. He received the title of Missionary Apostolic from Pope Clement XI which allowed him to focus his work on preaching a particular subject, Mary.
In 1715, he founded the missionary group the Company of Mary. He also founded the Congregation of the Daughters of Divine Wisdom who cared for the poor. His preaching on Mary included the Total Consecration to the Blessed Virgin as outlined in his book True Devotion to Mary. Louis believed that the souls consecrated to Mary would be the instrument in which the new Eve (Mary) crushes the serpent (the Devil/Antichrist). His writings inspired many to Marian consecration, including several popes.
St. Louis-Marie Grignion de Monfort died of natural causes in 1716. He was canonized in 1947, and his case to be made a Doctor of the Church is being investigated. His feast day is April 28.
I often have trouble with those that have such great devotions to Mary, for while I can agree with the theology behind it, the practice seems to lack tying Mary back to Christ. It is something I am emotionally foreign to, despite any intellectual agreement. I can understand where the cries of Mary worship come from when they look at consecrations to Mary, because I think some people get so caught up in the saint, they forget that the saint only wants to point to Christ. However, Louis always brought it back to its proper place; “God Alone” was his motto which he included to the ends of almost all his letters and hymns. A consecration to Mary is meant to enhance an already existing worship of God.