The origins of the Cistercian order are to be found in the events of 1098 at a prosperous monastery in Burgundy named Molesme. Unhappy at the wealth and status that the Molesme monastery had accumulated since it's founding some 20 years earlier, the founding abbot, Robert (d.1110), left and established a new monastery at Citeaux. It is the roman name of Cîteaux, Cistercium, that was to give the order its name. Dissatisfaction at the Molesme communities inability to observe the Rule of St. Benedict, led Robert to establish this new austere community in a place described as "a place of horror, a vast wilderness". Accompanying Robert in his new venture were 20 or 21 other monks from Molesme.
Unfortunately for Robert, the monks that remained at Molesme, unhappy at being left without an abbot and many of the senior brothers of the monastery, petitioned the Pope to make Robert return. Robert was forced to agree and returned to Molesme in 1099. The replacement for Robert was Alberic, who became abbot of Citeaux from 1099 until 1109. Upon his death Alberic was replaced by an Englishman, Stephen Harding, abbot 1109 until 1134.
The early years at Cîteaux were very hard. There was little or no support from the wealthy aristocracy that monastries relied upon, and the level of recruitment was very low. The turning point appears to have come early in the abbacy of Stephen Harding. Grants of land were received and recruits started to appear more frequently. By 1113 numbers at the monastery had grown sufficiently to support the first satelite monastery at La Ferté. 1113 also saw the arrival at Cîteaux of the man who was to become the most famous Cistercian, a young nobleman named Bernard of Fontaines. Bernard brought with him a string of family and friends whom he had persuaded to renounce the world. The growing number of novices led to further foundations: Pontigny (Yonne) in 1114; and Morimond (Haute-Marne) and Clairvaux (Aube) in 1115. Bernard was the founding abbot of Clairvaux, and was to remain in that office until his death in 1153.
What was revolutionary about the Cistercians, was that they developed
into an order with a constitution. This is the great achievement of Stephen
Harding. In 1119 Stephen presented Pope ClaxitusII the Carta Caritatis 'The
Charter of Love', which was in effect the constitution of the order. By this
time the order was growing rapidly, already in its 3rd generation, and Stephen
was determined that the young family should remain strong and not drift apart.
The Carta is uncompromising about the need for uniformity:
Therefore we will and command that everyone should observe the rule of St. Benedict in all matters as it is observed in the New Monastery ( Cîteaux).
Stephen also put in place two novel devices for ensuring the unity of the order. These were the annual General Chapter, and the process of annual visitation. It is not certain when these rules were introduced but they were regularized after 1119, and all abbots were required to present themselves at Cîteaux once a year at a date which came to be established as the feast of exaltation of the holy cross ( September 14). The initial purpose of this chapter was to strengthen the ties between Cîteaux and its offspring monasteries. Later it became the forum for establishing legislation, and disciplinary body of the order. The annual visitation was also meant to be a method of strengthening bonds. Every year each abbot was required to visit all daughter houses founded by his abbey, to ensure all was well. As the order spread geographically it became impossible for all abbots to attend every chapter and to make visitations every year. However the order was built on solid foundations and it continued to grow rapidly.In 1120 the order expanded beyond its Burgundian confines. La Ferté sent colonies to Tigletio (1120) in the diocese of Genoa, while Morimond established daughters in Germany at Camp (1123) and Ebrach (1123) and a granddaughter, via Bellevaux, at Lucelle in Alsace(1124). The Cistercian Order was well on its way to becoming a truly international order.
In 1128 the Cistercians made their first landfall in Britain, when a colony from l'Aumône (Loir-et-Cher), invited by bishop William Giffard of Winchester (1107-29), settled at Waverley. The new abbey was 26th in line from Cîteaux. On the 9th May 1131 the second British and first Welsh Cistercian settlement was made at Tintern, near Chepstow.
On the 5th March 1132, Rievaulx abbey was founded. It was to mark the start of an incredible 20 years expansion for the Cistercians in Britain, ending with the establishment of 86 houses across the length and breadth of the country.
The source for the above information is the fantastic book ' The Cistercan Abbeys of Britain' edited by David Robinson. It contains stacks of information regarding the formation and operation of the order as well as a comprehensive gazeteer of the abbeys in Britain. If you are at all interested in the order I would strongly recommend it.