Joseph was a friend of the astronomer Galileo. He spent 52 years as a priest who taught the faith to poor children. He organized teaching priests into a religious order called the Piarists.
"All who undertake to teach must be endowed with deep love, the greatest of patience, and, most of all, profound humility. They must perform their work with earnest zeal. Then, through their humble prayers, the Lord will find them worthy to become fellow workers with him in the cause of truth. He will console them in the fulfillment of this most noble duty, and finally, will enrich them with the gift of heaven."