Saint Louis de Montfort is known as the founder of the cult of the Virgin Mary in the Catholic Church. He devoutly adhered to Mariology and expounded on the benefits of saying the Rosary. As a result of his spiritual meditations, he wrote his most famous work: True Devotion to the Blessed Virgin. In this work, de Montfort developed the concept of voluntary spiritual slavery to the Virgin Mary in order to worship Christ in her and become like Christ. St Loius de Montfort's beliefs led to the development of several Catholic groups, the Brothers of St. Gabriel being one of the most enduring. With the support of these brothers, Pope John Paul II signed a treatise that supported and synthesized de Montfort's teachings into a single document. That year, the brothers also opened the Montfort Center.