Anthony Mary was an intense admirer of St. Paul, a model he imitated in the most decisive moments of his life.

Anthony Zaccaria was born in Cremona, Italy, toward the end of 1502. Since his childhood he distinguished himself by his piety, purity, and charity.
Anthony attended medical school at the University of Padua. Upon completion of his studies in Padua, Anthony returned to Cremona, but, instead of caring for physical infirmities, he "devoted himself to the life of the spirit."
In 1528 Anthony was ordained a priest and began his ministry of preaching God's Word and promoting the "renewal of Christian fervor."

In 1530 Anthony went to Milan and became a member of the Oratory of Eternal Wisdom where he met Bartolomeo Ferrari and Giacomo Antonio Morigia. With them and under the guidance of his spiritual director, Fra Battista da Crema, Anthony founded the Congregation of the Clerics Regular of St. Paul, approved by Pope Clement VII on February 18, 1533, and confirmed by Pope Paul III on July 24, 1535. The early Barnabites liked to call themselves "Clerics of St. Paul beheaded" for their resolve to imitate Paul even in his sufferings.

During these same years Anthony founded the congregation of the Angelic Sisters of St. Paul and formed the group, "The Marrieds of St. Paul."
The Sisters styled themselves "Angelics of St. Paul converted" on account of their special interest in Paul's, and their own ongoing, conversion.

Following the example of St. Paul and compelled by God's love, Anthony tirelessly preached the mystery of the Cross and of the Eucharist.

Exhausted by his zeal Anthony Zaccaria died in Cremona, in his mother's arms, on July 5, 1539.
An ancient tradition holds that, before expiring, Anthony Mary was granted a vision of St. Paul.
He was canonized by Leo XIII on May 27, 1897. His relics are venerated in the Church of St. Barnabas in Milan, Italy.

The only extant writings of St. Anthony M. Zaccaria are

• 12 letters, the best known of his writings
• 6 sermons
• an outline of the Constitutions for the Barnabites (which were never promulgated)
• some miscellaneous spiritual thoughts that appear here and there in late Barnabite writings

Anthony Mary's writings are all Pauline in nature, that is, grounded in, and integrated with, the teachings and sayings of St. Paul.
Anthony Mary's spirituality is totally inspired by St. Paul and is best expressed in Anthony's program for true, personal and collective, renewal of Christian fervor: "You are my crown and my glory, so much so that some day I will make our holy Apostle Paul feel envious of me on account of you. In fact you are not inferior to his [spiritual] daughters in your great desire to suffer for Christ, in your total contempt of worldliness and self-denial, and in your striving to lead people to a spiritual renewal and to Jesus Crucified who is dispised so much."
(Letter V)
This program is presented in the Barnabite Constitutions as (a) "pure self-contempt"; (b) "pure honor of Christ"; (c) "pure service of neighbor."
Inspired by St. Paul, Anthony Mary's spirituality is centered on the Crucified and Eucharistic Christ.

To promote devotion to Christ Crucified Anthony Mary instituted the practice of the tolling of church bells at 3 p.m. every Friday in remembrance of Christ's death on the cross.
He also advised people to make the cross of Christ the object of constant meditation, reflecting often on "the book that records the sweet memory of the cross of Christ" (Letter XI).

Anthony Mary promoted devotion to the Eucharistic Christ in the form of the Forty Hours devotion, public and solemn adoration of the Blessed Sacrament by turn in various city churches, which he first celebrated in Milan in 1537. He also promoted frequent Holy Communion.