
Peter had a strong Marian devotion, and travelled to the assorted Marian shrines and apparition sites in France. Organized laysocieties under the direction of the Marists, preached and taught, and worked for Eucharistic devotion. He felt a call to found a new religious society, and founded the Congregation of the Blessed Sacrament in 1856, and the lay Servants of the Blessed Sacrament in 1858. His work encountered a series of setbacks, including have to close his nascent houses and move twice, and the houses not being able to support themselves financially. However, his vision of priests, deacons, sisters, and lay people dedicated to the spiritual values celebrated in the Mass and prayer before the Blessed Sacrament anticipated many of the renewals brought about by Vatican Councils I and II.
Late in life, during a lengthy retreat in Rome, he became more mystical as he came in closer communion with the love of Christ. Six volumes of his personal letters, and nine volumes of his meditations have been printed in English.