St. John Leonardi
Saint John Leonardi (1541-1609) was born in Tuscany and, after studying to become a pharmacist, left this profession and was ordained to the priesthood in 1572. He devoted himself to teaching catechism to children; in addition, he gathered laymen to work with him in hospitals and prisons, and in 1574 he founded the Order of Clerics Regular of the Mother of God. He later founded in Rome a society of priests dedicated to serving in foreign missions; this eventually became the Society for the Propogation of the Faith.
In 1579 he formed the Confraternity of Christian Doctrine, and published a compendium of Christian doctrine that remained in use until the 19th century. He died in 1609, from a disease caught while tending plague victims.
John was canonized in 1938.