Joseph Calasanz, Spanish priest and founder of Piarists (d. 1648)
Joseph Calasanz (Spanish: José de Calasanz; Italian: Giuseppe Calasanzio), (September 11, 1557 – August 25, 1648), also known as Joseph Calasanctius and Iosephus a Mater Dei, was a Spanish Catholic priest, educator and the founder of the Pious Schools, providing free education to the sons of the poor, and the Religious Order that ran them, commonly known as the Piarists. He was a close friend of the renowned astronomer Galileo Galilei. He is honored as a saint by the Catholic Church.