Stanislaus was soon conspicuous among his classmates during his three years of schooling, not only for his amiability and cheerfulness of expression, but also for his growing religious fervour and piety.

[2] His brother Paul said during the process of beatification that "He devoted himself so completely to spiritual things that he frequently became unconscious, especially in the church of the Jesuit Fathers at Vienna."

One of the practices of devotion which he joined while at Vienna was the Congregation of St. Barbara and Our Lady, "of which he, with numbers of the pupils of the Society of Jesus" also belonged.

[3] Stanislaus alleged to a fellow-member of the Society at Rome that Saint Barbara brought two angels to him during the course of a serious illness, in order to give him the Eucharist.

At Vienna they hesitated to receive him, fearing the tempest that would probably be raised by his father against the Society, which had just quieted a storm unleashed by other admissions to the Company.

They started to follow him, but were not able to overtake him; either their exhausted horses refused to go further, or a wheel of their carriage would break, or, as the tutor frankly declared, they had mistaken the route, having left the city by a different road from the one which Stanislaus had taken.

It is noticeable that in his testimony Paul gives no explanation of his ill-luck.Stanislaus stayed for a month at Dillingen, where the provincial of that time, Saint Peter Canisius, put the young aspirant's vocation to the test by employing him in the boarding-school.

During the ten remaining months of his life, according to the testimony of the master of novices, Father Giulio Fazio, "he was a model and mirror of religious perfection.

He wrote a letter to the Blessed Virgin begging her to call him to the skies there to celebrate with her the glorious anniversary of her Assumption (15 August).

In his message, Pope Francis cites a maxim of Stanislaus's: “Ad maiora natus sum – 'I was born for greater things'".

Her sister Pauline had asked Thérèse to write verses and theatrical entertainment for liturgical and community festivals.