Religious Orders, the term applied to associations of men or women in the Roman Catholic church and the oriental churches, whose members live in common in convents. The history of these associations is given in the article Monachism. The common bond of union among all the religious orders, and which distinguishes them from other classes of associations, is retirement from the world, celibacy, and their organization, by means of religious vows, into communities of an entirely ecclesiastical character. The official list in the Gerarchia Cattolica of 1875, published in the Vatican, divides religious orders into six classes: 1, the regular canons, comprising the regular canons of the Most Holy Saviour of the Lateran, those of the basilica of Santa Croce, and the Premonstratensians; 2, regular clerks, embracing Theatins, Barnabites, Somaschians, Jesuits, minor clerks, ministers of the infirm, fathers, of the Mother of God, and fathers of the pious schools, or Piarists; 3, religious congregations, including the Passionists and Re-demptorists; 4, ecclesiastical congregations, including the Doctrinarians, Lazarists or priests of the mission, pious laborers, oblates of Mary Immaculate, missionaries of the Precious Blood, institute of charity (Rosmini's), priests of the Sacred Hearts of Jesus and Mary, priests of the society of missions, priests of the resurrection, priests of the Holy Cross (of Le Mans), brothers of the Christian schools, and brothers of mercy; 5, monks, including the Basilians, Benedictines, Camaldules, hermits of Tuscany, hermits of Monte Corona, hermits of Vallombrosa, Cistercians, Trappists, Trappists of the Rancé reform, Benedictines of Monte Vergine, Olive-tans, Silvestrines, Chartreux, Antonians (comprising Chaldeans, Maronites, and Armenians of Mt. Lebanon), Mekhitarists or Armenian Benedictines, and Basilians of the Greco-Mel-chite rite, comprising the Joanites of Palestine; 6, mendicants, including the Dominicans, minor Observants (comprising the reformed Observants, the minor Recollects, and Alcan-tarines), minor Conventuals, minor Capuchins, third order of St. Francis, Augustinians and discalced Augustinians, Carmelites of the primitive observance and reformed Carmelites, Ser-vites or servants of Mary, Minims, Mercedari or fathers of the redemption of slaves, Trinitarians (primitive and reformed), Hieronymites or order of St. Jerome, hospitallers of St. John of God, and fathers of penitence.

This classification is founded on the original distinction between the clergy or ordinary ministers of religion and the monks, who in the beginning were mostly or exclusively laymen, or who when priests lived in seclusion, and had no share in the ministrations of the clergy. The partly or wholly monastic forms adopted after the 4th century in the East, and especially in the West, by the cathedral and parochial clergy, caused them to be generally designated as clerici canonici. But this designation, particularly during the reign of feudalism, came to be applied exclusively to the clergy of cathedral or collegiate churches, who lived in common under some such rule as that of St. Augustine. This gave rise to the institution of canons regular. The parochial clergy were organized in this way by Eusebius, bishop of Vercelli (died 370), by St. Ambrose (died 397) in Milan, and by St. Augustine (died 430) at Hippo. This quasi-monastic form was propagated by St. Gregory the Great in Sicily and in Rome before his elevation to the papacy, and according to Lingard it was established in England by Augustin, archbishop of Canterbury, and prevailed in the chief churches there till supplanted by the strict Benedictine rule.

The whole clergy of the British islands, as well as of several continental countries, continued at least during the missionary epoch to live in establishments called monasteries by contemporary writers, though distinguished by them into clerical and monastic houses. Thus the first great class of religious associations embraces those anciently designated as the "regular clergy," that is, persons who were by vocation clergymen and embraced a monastic form of life; while the second class, or monks proper, comprises persons who are devoted to a life of seclusion, and are supposed to engage only by accident in the active ministrations of the parochial clergy. Hence both in time and in dignity the regular clergy are first. The canons regular of all denominations were always held by their rule to the public recitation or chanting of the divine office. The regular clerks of the society of Jesus were the first to deviate from this custom; and their exemption from choral service caused them to be bitterly assailed by other religious orders, who for this very reason refused for a long time to acknowledge them as one of the monastic brotherhoods.

The third group of regular clerks, consisting of the Passionists and Redemptorists, are called in the list "religious congregations," because their vows have less of solemnity than those of the Jesuits, and are more binding than those of the following groups. They are, besides, held to recite the office in common. The members of the "ecclesiastical congregations" are held together by simple vows of obedience and poverty, or by promises of fidelity to their respective rules, and aim at discharging the clerical functions, or some duties closely connected therewith, such as the instruction of youth. - The monks proper are subdivided into two great families. The distinctive characteristics of the first are a life of seclusion, varied in some groups, like the Benedictines, by devotion to literary culture, and in others, like the Trappists, by a seeking after penitential austerity. The mendicants originally aimed at combining the contemplative and austere retirement of the monk with the active ministrations of the canons regular.

They obtained their early reputation and popularity by living in poverty, prayer, and self-abnegation in the midst of the people to whose spiritual needs they ministered. - To most of the religious orders, soon after their formation, nuns of the same rule attached themselves. They were often called the second branch of the order, and their convents were generally under the ecclesiastical jurisdiction of the priests of the order. Besides the nuns, most of the orders received numerous additions by admitting lay brothers (fra-tres conversi) or lay sisters (sorores conversoe), who were charged with the performance of the housework and with keeping up communication with the world. - The Protestant churches in general have declared themselves opposed to the fundamental principle of monastic institutions; but in modern times several such communities, living in common and binding themselves to the observance of a rule, have been formed. In the church of England an institution of sisterhoods has been considerably extended under the auspices of the so-called high church party.

More recently an Anglican clergyman, the Rev. Mr. Lyne, assuming the name of Father Ignatius, endeavored to establish an Anglican branch of the Benedictine order; but the first monastery at Norwich, after the trial of a few years, had to be abandoned. Another clergyman tried to revive the Canons regular of the Augustinian order, but, although the number of those who advocate the revival of monasticism in the church of England has considerably increased, notable results have not yet been obtained. In the Evangelical church of Germany communities of women, called deaconesses, were established for charitable purposes, especially for nursing the sick. This institution has assumed large dimensions and established branches in many other countries. (See Deaconesses.) The most curious example of a Protestant religious order is found in the United States, among the Seventh-Day German Baptists or Seventh-Day Dunkers. (See Dunkers).