At age seven he experienced a profound spiritual quickening. His prayers included the Office of Mary, the psalms and other devotions. At age nine he came from his hometown of Castiglione to Florence to be educated; by age 11 he was teaching catechism to poor children, fasting three days a week and practicing great austerities. When he was 13 years old he traveled with his parents and the Empress of Austria to Spain and acted as a page in the court of Philip II. The more Aloysius saw of court life, the more disillusioned he became, seeking relief in learning about the lives of saints.

A book about the experience of Jesuit missionaries in India suggested to him the idea of entering the Society of Jesus, and in Spain his decision became final. Now began a four-year contest with his father. Eminent churchmen and laypeople were pressed into service to persuade him to remain in his "normal" vocation. Finally he prevailed, was allowed to renounce his right to succession and was received into the Jesuit novitiate.

Like other seminarians, Aloysius was faced with a new kind of penance-that of accepting different ideas about the exact nature of penance. He was obliged to eat more, to take recreation with the other students. He was forbidden to pray except at stated times. He spent four years in the study of philosophy and had St. Robert Bellarmine (September 17) as his spiritual adviser.

In 1591, a plague struck Rome. The Jesuits opened a hospital of their own. The general himself and many other Jesuits rendered personal service. Because he nursed patients, washing them and making their beds, Aloysius caught the disease himself. A fever persisted after his recovery and he was so weak he could scarcely rise from bed. Yet, he maintained his great discipline of prayer, knowing that he would die within the octave of Corpus Christi, three months later, at the age of 23.