On 2 July 1654, Papczyński joined the Piarist Order, newly established in Poland, in their monastery in Podoliniec and was given the religious name of "Stanislaus of Jesus and Mary".

From the perspective of his whole life's experience, he thus described in his testimony one incident from those days: "I confess," he writes, "that I leave this world professing the Catholic faith for which I was ready to pour out my blood during the war with Sweden.

One day my companion and I were exiting the Old Town, when a heretic soldier, his unsheathed sword in hand, attacked us near the Dominican Fathers.

Taking advantage of Papczyński's contacts with influential people, his superiors entrusted him with gathering petitions for the beatification of the Order's founder, Joseph Calasanz.

In those difficult times he wrote two series of meditations: Orator crucifixus (The crucified Speaker) and Christus patiens (The suffering Christ).

Not being able to find for himself, within the Piarists, the proper climate for life and work and at the same time seeing also a rift within the Province between his supporters and adversaries, Papczyński asked the Superior General to release him from his religious vows.

Consequently, I vow to serve Them zealously, in chastity, to the end of my life, in the society of Marian Clerics of the Immaculate Conception, which by the grace of God I wish to found".

Papczyński's mission was made more difficult by his being of common birth and advocating a very rigorous lifestyle in the prevalent aristocratic mentality.

At the same time he wrote a moral and ascetical treatise called "Templum Dei Mysticum" (The Mystical Temple of God), which underwent several reprints.

Seeking candidates for his planned order, in September 1673, Papczyński went to Puszcza Korabiewska near Skierniewice, where a former soldier, Stanislaus Krajewski, and companions lived as hermits.

Bishop Stanislaus Święcicki, who came on a canonical visitation on 24 October 1673, approved this community living in accord with the "Norma vitae" under Papczyński's guidance.

The stated goal of the community was to spread devotion to the Virgin Mary, and to assist poor souls in purgatory, particularly those who died in fields of battle and victims of plagues.

However, the simple vows which the Marians were making at the time were not strongly binding, and the fate of the Congregation depended simply on the bishop.

In 1699, Papczyński made another attempt to procure the approbation of his order, by sending to Rome Joachim Kozlowski as his envoy with full powers (plenipotentiary).

At school, from the pulpit, in confessional, or at his desk, Papczyński proclaimed the word of God everywhere in speech and writing, emphasizing particularly the need to care for those wronged by the society.

[5] But because such a long time had passed since his death, this process had to be accomplished "historically", which means that documents had to be searched for testimonies on one's life and virtues.

On 28 February 1980, the National Conference of Bishops in Poland petitioned the Pope to elevate Papczyński to the altars as a model of Christian life.

Based on this evidence, on 28 November 1980, the Congregation for Saints made a decision that Papczyński's beatification cause may be brought before the Apostolic Tribunal.

Pope John Paul II approved this decision on 6 March 1981 which commenced sainthood proceedings and granted him the title Servant of God – the first stage in the process.

Then, on 22 January 1991, during an Ordinary Congress of the Congregation, chaired by Anthony Petti, General Promoter of the Faith, the theological consultants stated that Papczyński had practiced virtues to a heroic degree.

After the results of the research conducted by the Cardinal-Prefect, Cardinal Angelo Felici, had been presented to the pope, he accepted the decision of the Sacred Congregation for the Causes of the Saints and ordered that the decree on Papczyński's heroic virtues be prepared.

He was beatified at the Marian Shrine in Licheń by a special delegate of Pope Benedict XVI – Cardinal Tarcisio Bertone, Secretary of State of the Holy See on 16 September 2007.

I fall at the feet of Blessed Virgin Mary, Mother of God, and I give myself with the entire Congregation of her Immaculate Conception to her for eternity.

I call on her gracious direction and effective care, and for the hour of my death I beg her most merciful and powerful protection from the ambushes of my enemies and all temporal and eternal Evil.