At the age of nineteen, she entered the recently formed Congregation of the Franciscan Sisters of the Afflicted founded by Honorat Koźmiński, whose purpose was to care for the sick.

On 8 September 1887, she formed on Koźmiński's advice, with five other women, a covert religious community in the ancient city of Płock and went to live with them.

[3] She became superior of the new community, called the Congregation of Sisters of the Poor of Saint Mother Clare and took the religious name Maria Franciszka.

In time the needlework brought in commissions from wealthy clients which improved the material position of the women, while Kozłowska fostered their spiritual development.

[4] In 1890 her widowed mother, Anna Kozłowska, having sold her properties in Warsaw, decided to move to Płock and live with her daughter.

The reasons were that he disapproved of the attitude of some of his clerical brethren who, though educated and pious, had fallen under her spell and took spiritual direction from a woman.

The first vision supposedly instructed her to form a new clergy order with the primary goal of propagating the Adoration of the Blessed Sacrament and devotion to Our Lady of Perpetual Succour.

Kozłowska, not wishing to create difficulties with the church authorities, largely stayed out of public view and left the structural and political implications of the movement to others, particularly to Kowalski.

In an effort to regularise the movement in the eyes of the Catholic Church, the group submitted documents to the local Bishop of Płock, in whose diocese Kozłowska lived and to two leading archbishops.

Kowalski and his fellow Mariavites were severely disappointed when, in August 1904, the Congregation of the Roman and Universal Inquisition (CRUI) concluded that Kozłowska's "visions" were mere hallucinations.

In November 1906, only a month prior to the ex-communication from the Catholic Church, the Russian government granted the movement official status in the part of Poland under its control after the October Manifesto granting everyone freedom of religion and so a split in the Polish Roman Catholic Church (her enemies supported the idea that could help foster a split in manifest Polish nationalism as well).

The hagiographic nature of this work and the "elevation" of Kozłowska to a status apparently co-equal with that of the Blessed Virgin Mary, if not with the Holy Spirit, was excessive even to many Mariavites.