a religious order founded A.D. 1098, by St Robert, abbot of Molesme. It was so named from its original convent in the forest of Citeaux (Cistercium), about 14 miles N.E. of Beaune. This order became so powerful that it governed almost all Europe both in temporal and spiritual concerns; and through the exertions of St Bernard of Clairvaux had increased so rapidly in power, that within a century from its foundation it embraced 800 rich abbeys in different countries of Europe. Their rule was that of St Benedict. The Cistercians devoted themselves to a contemplative life, and practised great austerities. The abbeys of La Ferté, Pontigny, Clairvaux, and Morimond, were offshoots of that of Citeaux; and produced in their turn a great number of separate communities, all which continued under the superintendence of the abbey of Citeaux. The abbey of Morimond alone possessed 700 benefices; and its supremacy was acknowledged by the military orders of Calatrava, Alcantara, and Montesa in Spain, and those of Christ and of Avis in Portugal. But the most famous of all the communities of this order was that of Clairvaux, founded by St Bernard. (See Bernard, St.) Towards the end of the twelfth century, however, the immense wealth of Citeaux began to operate unfavourably on its discipline, and led the way to great corruptions. Jean de la Barrière, abbot of Notre-Dame des Feuillants, near Toulouse, succeeded in 1577 in effecting a reform, which gave rise to the Feuillants in France; and likewise to the reformed Bernardines in Italy. But of all the reforms among the Cistercians, the most celebrated was that effected by the abbot of La Trappe in 1664.

Dependent on the abbey of Citeaux there were about 1800 monasteries and an equal number of nunneries. This ancient abbey was the burial-place of all the dukes of Burgundy of the original line, with the exception of the first two, who died before its foundation. Citeaux has produced, besides St Bernard, two popes (or four according to some), and a great number of cardinals. The remains of this great abbey still exist.

The Cistercians were involved in the general fate of the religious orders during the period of the French revolution of 1789; and they were reduced to a few convents in Spain, Poland, the Austrian dominions, and the Saxon part of Upper Lusatia. Their habit is a white robe or cassock, with a black scapulary, and a woollen girdle. The nuns wear a white tunic and a black scapulary and girdle.—(Manriquez, Annales Cistercienses, 4 vols. folio, Lyons, 1642.)