Roman Curia 
The highest-ranking departments of the Roman Curia are called congregations. Lower-ranking are the pontifical councils and pontifical commissions. Others are tribunals and offices.
In origin, the congregations were selected groups of cardinals, not the whole College of Cardinals, commissioned to take care of some field of activity that concerned the Holy See. Today, as a result of a decision of the Second Vatican Council, the membership includes diocesan bishops from diverse parts of the world who are not cardinals. Each congregation also has a permanent staff to assist it in dealing with the business that comes before it.
Religious institutes 
Augustinian, Benedictine and Cistercian congregations 
A group of monasteries or of chapters of canons regular is called a congregation. Each congregation is presided over by a superior with a title such as abbot general, archabbot, abbot president, president, abbot ordinary, provost general or superior general. The generic term for such a superior is "abbot primate".
The Annuario Pontificio lists the following as the congregations of the Canons Regular of Saint Augustine, whose abbot primate lives in Rome:
- Canons Regular of the Congregation of the Most Holy Saviour of the Lateran (abbot general in Rome)
- Canons Regular of the Austrian Lateran Congregation (1907 – abbot general in Klosterneuburg, Austria)
- Canons Regular of the Hospitalary Congregation of Great Saint Bernard (11th century – provost gerneral in Martigny, Switzerland)
- Canons Regular of the Swiss Congregation of Saint-Maurice of Agaune (1128 – abbot ordinary in Saint-Maurice, Switzerland)
- Canons Regular of Saint Augustine of the Congregation of Windesheim (1386 – provost general in Paring, Germany)
- Canons Regular of the Congregation of Saint Victor (1968 – abbot general in Champagne-sur-Rhône, France)
- Canons Regular of the Immaculate Conception (1866 – superior general in Rome)
- Canons Regular of the Congregation of the Brothers of Common Life (14th century – superior general in Weilheim, Germany)
- Cassinese Benedictine Congregation (1408 – president in Rome)
- English Benedictine Congregation (1336 – president in Radstock, England)
- Hungarian Benedictine Congregation (1514 – archabbot in Pannonhalma, Hungary)
- Swiss Benedictine Congregation (1602- president in Bolzano, Italy)
- Austrian Benedictine Congregation (1625 – president in Stift Göttweig, Austria)
- Bavarian Benedictine Congregation (1684 – president in Kloster Schäftlarn, Germany)
- Brazilian Benedictine Congregation (1827 – president in Salvador, Brazil)
- Solesmes Benedictine Congregation (1837 – president in Sablé-sur-Sarthe, France)
- American Cassinese Benedictine Congregation (1855 –president in Collegeville, United States)
- Subiaco Benedictine Congregation (1872 – the president lives in Rome)
- Beuron Benedictine Congregation (1873 – the president lives in Maria Laach, Germany)
- Swiss-American Benedictine Congregation (1881 – the president lives in St. Benedict, United States)
- St. Ottilien Benedictine Congregation (1884 – archabbot president in St. Ottilien, Germany)
- Annunciation Benedictine Congregation (1920 – president in Trier, Germany
- Slav Benedictine Congregation (1945 – prior administrator in Prague, Czech Republic)
- Olivetan Benedictine Congregation (1319 – abbot general in Chiusure, Italy)
- Vallombrosan Benedictine Congregation (1036 – abbot general in Vallombrosa, Italy)
- Camaldolese Congregation of the Order of Saint Benedict (980 – prior general in Camaldoli, Italy)
- Sylvestrine Benedictine Congregation (1231 – abbot general in Rome)
- Benedictine Congregation of the Holy Cross of the Southern Cone (1976 – president in Los Toldos, Argentina)
The Annuario Pontificio lists the following congregations of Cistercians. Their abbot primate is called instead abbot general.
- Castilian Cistercian Congregation (1425 – the abbot general acts as pro-president)
- Cistercian Congregation of St Bernard in Italy (1497 – abbot president in San Severino Marche, Italy)
- Cistercian Congregation of the Crown of Aragon (1616 – abbot president in Poblet, Spain)
- Mehrerau Cistercian Congregation (1624 – abbot president in Bregenz, Austria)
- Cistercian Congregation of Mary Mediatrix (1846 – abbot president in Nieuwkuijk, Netherlands)
- Austrian Cistercian Congregation (1859 – abbot president in Heiligenkreuz, Austria)
- Cistercian Congregation of the Immaculate Conception (1867 – abbot president in Ile Saint Honorat, France)
- Zirc Cistercian Congregation (1923 – abbot president in Zirc, Hungary)
- Cistercian Congregation of the Immaculate Heart of Mary (1923 – abbot president in Rome)
- Casamari Cistercian Congregation (1929 – abbot president in Casamari, Italy)
- Cistercian Congregation of Mary Queen of the World (1953 – abbot president in Kraków, Poland)
- Brazilian Cistercian Congregation (1961 – abbot president in Itaporanga, Brazil)
- Cistercian Congregation of the Holy Family (1964 – abbot president in Thành-Phô Ho Chí Minh, Vietnam)
Congregations as a historical category of religious institutes 
By the constitution Inter cetera of 20 January 1521, Pope Leo X appointed a rule for tertiaries with simple vows. Under this rule, enclosure was optional, enabling non-enclosed followers of the rule to engage in various works of charity not allowed to enclosed religious. In 1566 and 1568, Pope Pius V rejected this class of institute, but they continued to exist and even increased in number. After at first being merely tolerated, they afterwards obtained approval. Their lives were oriented not to the ancient monastic way of life, but more to social service and to evangelization, both in Europe and in mission areas. Their number increased further in the upheavals brought by the French Revolution and subsequent Napoleonic invasions of other Catholic countries, depriving thousands of monks and nuns of the income that their communities held because of inheritances and forcing them to find a new way of living their religious life. Only on almost the last day of the 19th century were they officially reckoned as religious, when Pope Leo XIII recognized as religious all men and women who took simple vows in such congregations.
The 1917 Code of Canon Law reserved the name "religious order" for institutes in which the vows were solemn, and used the term "religious congregation" or simply "congregation" for those with simple vows. The members of a religious order for men were called "regulars", those belonging to a religious congregation were simply "religious", a term that applied also to regulars. For women, those with simple vows were simply "sisters", with the term "nun" reserved in canon law for those who belonged to an institute of solemn vows, even if in some localities they were allowed to take simple vows instead.
However, it abolished the distinction according to which solemn vows, unlike simple vows, were indissoluble. It recognized no totally indispensable religious vows and thereby abrogated spiritually, though not altogether juridically, Latin-Rite religious orders. Solemn vows were originally considered indissoluble. Not even the Pope could dispense from them. If for a just cause a solemnly professed religious was expelled, the vow of chastity remained unchanged and so rendered invalid any attempt at marriage, the vow of obedience obliged in relation, generally, to the bishop rather than to the religious superior, and the vow of poverty was modified to meet the new situation, but the expelled religious "could not, for example, will any goods to another; and goods which came to him reverted at his death to his institute or to the Holy See".
After publication of the 1917 Code, many institutes with simple vows appealed to the Holy See for permission to make solemn vows. The Apostolic Constitution Sponsa Christi of 21 November 1950 made access to that permission easier for nuns (in the strict sense), though not for religious institutes dedicated to apostolic activity. Many of these institutes of women then petitioned for the solemn vow of poverty alone. Towards the end of the Second Vatican Council, superiors general of clerical institutes and abbots president of monastic congregations were authorized to permit, for a just cause, their subjects of simple vows who made a reasonable request to renounce their property except for what would be required for their sustenance if they were to depart, thus assimilating their position to that of religious with solemn vows. These changes resulted in a blurring of the previously clear distinction between "orders" and "congregations", since institutes that were founded as "congregations" began to have some members who had all three solemn vows or had members that took a solemn vow of poverty and simple vows of chastity and obedience.
The current Code of Canon Law, which came into force in 1983, maintains the distinction between solemn and simple vows, but no longer makes any distinction between their juridical effects, including the distinction between "orders" and "congregations". It has accordingly dropped the language of the 1917 code and uses the single term "religious institute" (which appears nowhere in the 1917 Code) to designate all such institutes of consecrated life alike.
In the current Code of Canon Law, the word "congregation" is never used of a class of religious institutes, but only of the congregations of the Roman Curia or of monastic congregations. In the English translation of the Canon Law Society of America, the word "congregation" is used also in canon 767 §§2-3 of the people at Mass, where the Latin text has "populi concursus", not "congregatio".
The Annuario Pontificio lists for both men and women the institutes of consecrated life and the like that are "of pontifical right" (those that the Holy See has erected or approved by formal decree). For the men, it gives what it calls the Historical-Juridical List of Precedence. In this list it maintains to a large extent the historical distinction between "orders" and "congregations", giving information on 96 "clerical religious congregations" and 34 "lay religious congregations", but it does not distinguish, even for men, between "orders" and "congregations" of Eastern Catholic Churches, nor does it distinguish between these two pre-1983 classes when listing the pontifical-right religious institutes of women. These are much more numerous than those for men. The Annuario Pontificio devotes 216 pages to listing them, with 6 or 7 of them (mostly 7) on each page.
See also 
- Consecrated life (Catholic Church)
- Institute of consecrated life
- Religious institute
- Catholic religious order
- Secular institute
- Society of apostolic life
- The Roman Curia, index to departments
- Annuario Pontificio (Libreria Editrice Vaticana 2012 ISBN 978-88-209-8722-0), pp. 1411-1413)
- Annuario Pontificio 2012, pp. 1414-1419
- Annuario Pontificio 2012, pp. 1419-1422
- Arthur Vermeersch, "Religious Life" in The Catholic Encyclopedia, Vol. 12. New York: Robert Appleton Company, 1911. Accessed 18 July 2011
- "Illud solum votum debere dici solemne . . . quod solemnizatum fuerit per suceptionem S. Ordinis aut per professionem expressam vel tacitam factam alicui de religionibus per Sedem Apostolicam approbatis" (C. unic. de voto, tit. 15, lib. III in 6, quoted in Celestine Anthony Freriks, Religious Congregations in Their External Relations, p. 17).
- Constitution "Conditae a Christo" of 8 December 1900, cited in Mary Nona McGreal, Dominicans at Home in a New Nation, chapter 11
- 1917 Code of Canon Law, canon 488
- Thomas Aquinas, Summa Theologica, II-II, q. 88, a.11
- Paul M. Quay, "Renewal of Religious Orders, or Destruction?", in Commentarium pro Religiosis et Missionariis, vol. 65 (1984), pp. 77-86
- Yūji Sugawara, Religious Poverty: from Vatican Council II to the 1994 Synod of Bishops (Loyola Press 1997 ISBN 978-88-7652-698-5), pp. 127-128
- Code of Canon Law, canon 1192 §2
- IntraText concordance to the 1917 Code
- Robert T. Kennedy, Study related to a pre-1983 book by John J. McGrath – Jurist, 1990, pp. 351-401
- IntraText concordance of the English translation
- Code of Canon Law, canon 589
- Annuario Pontificio 2012 (Libreria Editrice Vaticana 2012 ISBN 978-88-209-8722-0), pp. 1411-1429