Charles Buck Theological Dictionary 
A religious order founded by St. Robert, a Benedictine, in the eleventh century. They became so powerful, that they governed almost all Europe both in spirituals and temporals. Cardinal de Vetri, describing their observances, says, they neither wore skins nor shirts, nor ever ate flesh, except in sickness; and abstained from fish, eggs, milk and cheese: they lay upon straw beds in tunics and cowls; they rose at midnight to prayers; they spent the day in labour, reading, and prayers; and in all their exercises observed a continual silence.
Cyclopedia of Biblical, Theological and Ecclesiastical Literature 
(or CISTERTIANS), an order of monks founded in the year 1098 by Robert, a Benedictine, and abbot of Moleme, in Burgundy. Finding it impossible to preserve discipline in his convent, he retired, with twenty of his best monks, to Citeaux, in the diocese of Chalons, where he laid the foundations of the famous order named from the place. Robert, being ordered by the pope to resume the government of the abbey of Moleme, was succeeded in that of Citeaux by Alberic; and pope Paschal II, by a bull of the year 1100, took Citeaux under his protection. Alberic drew up the first statutes for the monks of Citeaux, or Cistercians, in which he enjoined a strict observance of the rules of St. Benedict.
The habit of the order was a white robe in the form of a cassock: it was at first black; but they pretend that the holy Virgin, appearing to Alberic, gave him a white habit, and from-this time they changed the black for white, retaining the black scapular and hood: their garment was girt with a black girdle of wool: in the choir they had a white cowl, and over it a hood, with a rochet hanging down before to the waist, and in a point behind to the calf of the leg. In memory of the change of habit, a festival was observed on the 5th of August, called "The descent of the blessed Virgin at Citeaux, and the miraculous changing from black to white." The order made surprising progress. "From the very first, the Cistercians were the spoiled children of the apostolic see, and every conceivable privilege and exemption was heaped upon them" (Christian Remembrancer, July, 1867, p. 4). About 1128 the first Cistercian abbey in England was founded by Giffard, bishop of Winchester, at Waverley, Surrey. The order spread in England rapidly, and accumulated vast estates. Eighty-five abbeys in various parts of England owned the maternity either of Citeaux or Clairvaux. Fifty years after its institution the order had five hundred abbeys; and one hundred years after it boasted of one thousand eight hundred abbeys, most of which had been founded before the year 1200.
The government of the order was in the hands of twenty-five definitores, the first of whom was the abbot of Citeaux, who, as abbot general, was the head of the whole order. Next to him in dignity were the abbots La Ferte, Pontigny, Clairvaux, and Morimond, the four oldest convents after Citeaux. The abbot of Citeaux appointed four other definitores. The abbots of La Ferte, Pontigny, Clairvaux, and Morimond nominated together twenty (five each), four of whom, i.e. one of each nomination, were rejected by the abbot general. The legislative assembly, called the General Chapter, met originally annually. They did not settle in any diocese before the bishop had accepted the Charta Charitatis, the fundamental law of the order, which had been given in 1119 by abbot Stephen of Citeaux. In 1143 the king of Portugal imposed upon his whole kingdom the duties of vassalage towards the abbey of Clairvaux, so that (in 1578) claims were laid by the latter to all Portugal.
The decay of the Cistercians began with the rise of the mendicant orders. Their history consists mostly in efforts of popes and some abbots to stay the flood of corruption which early overflowed the whole order. These efforts were usually unsuccessful, but led to the establishment of a number of reformed congregations, which received from the popes the privilege of an independent organization. The most important are those founded in Spain in 1469, in Tuscany in 1497, and that founded by pope Urban VIII in 1630. The present number of abbeys is very limited. There were in 1843 16 abbeys, with 499 members, in Austria; 9 in Italy, several of which have since been suppressed by the Sardinian government; 3 in Switzerland, of which one has since been suppressed; 1 in Belgium; and 1 in Poland. Since then they have re- established themselves also in England, at St. Susan's, Lullworth, and Mount St. Bernard, in Leicestershire. Several other monastic organizations owe their origin directly or indirectly to the Cistercians. The Templars received their rule from St. Bernard of Clairvaux. The Spanish knights of Calatrava, Alcantara, and Montesa, and the Portuguese of Avis and Christ, were affiliated to the Cistercians. The Feuillants took their origin in 1574 in the reformed Cistercian abbey of Feuillans, near Toulouse. The austerest congregation that sprung from them are the Trappists, founded in 1662. See Fehr, Geschichte der Monchsorden, 1, 90 sq.; A concise History of the Cistercian Order (London, 1852, sm. 8vo); Maillard, Dark Ages, p. 358; Luard, Annales Monastici, vols. 1, 2 (Lond. 1864, 1865); Christian Remembrancer, July, 1867, art. 1. (See Trappists).
The Nuttall Encyclopedia 
A monastic order founded by Abbot Robert in 1098 at Citeaux, near Dijon; they followed the rule of St. Benedict, who reformed the Order after it had lapsed; became an ecclesiastical republic, and were exempt from ecclesiastical control; contributed considerably to the progress of the arts, if little to the sciences.