PIARISTS, the popular name of the “clerici regulares scholarum piarum," the Pauline Congregation of the Mother of God, which was founded by Joseph Calasanza (Josephus a Matre Dei) at Rome in the beginning of the 17th century. Calasanza, a native of Calasanz in the province of Huesca in Aragon, was born on September 11, 1556, studied at Lerida and Alcala, and after his ordination to the priesthood removed to Rome. Here he became zealously interested in the education of poor and orphan children, and with this end he organized, in 1607, a brotherhood which ultimately, in 1617, became an independent Congregation, numbering at that time fifteen priests, under Calasanza as their head. To the three usual vows they added a fourth, that of devotion to the gratuitous instruction of youth. In 1622 the Congregation received a new constitution from Gregory XV., and had all the privileges of the mendicant orders conferred upon it, Calasanza being recognized as general. In this capacity he busied himself with the extension of the order, not only in Italy, but also in Germany, Poland, and other countries, until 1643, when the jealousy of the Jesuits led to conflicts which resulted in his removal from office; owing to the same cause the Congregation was deprived of its privileges by Innocent X. in 1646. Calasanza, who died on August 22, 1648, was beatified in 1748, and canonized in 1767. The privileges of the Congregation were successively restored in 1660, 1669, and 1698. The Piarists, who are not a numerous body, are found chiefly in Italy, Spain, the West Indies, Germany, and especially in Austria-Hungary.