St. John Leonardi was born in 1541 as a member of the middle class. He was the youngest of seven children, and at age 17, he began studying to become a pharmacist. After 10 years of school, he became certified to practice, but followed his true calling to become a priest.
In 1572, John was ordained, and became a spiritual director to a group of young men who were studying to become priests. Their communal life would eventually lead to what is called the Order of the Mother of God (or Clerks Regular of the Mother of God) today.
The civic leaders in Lucca opposed the creation of this new order, and tried to stop John. Although they did not succeed, John was forced to leave Lucca for most of his life.
John and his congregation sought to deepen the practice of the faith among the clergy and lay Catholics, as part of the Counter-Reformation that followed the Council of Trent. In 1595, John received Papal approval for the Order of the Mother of God. He was also chosen to oversee reforms in two monasteries, and he founded a seminary for foreign missionaries, which is now the College for the Propagation of the Faith.
John died on Oct. 9, 1609, in Rome, after contracting a deadly disease while caring for victims of the plague. He was canonized in 1938 by Pope Pius XI. He is the patron saint of pharmacists.