A Roman Catholic order formed in 1098 by Benedictine monks and led by St. Robert of Molesme in Citeaux, France. Cistercians abide by a strict interpretation of St. Benedict's rule and emphasize solitude, poverty, uniformity, and especially manual labor. The order was prominent during the Middle Ages, particularly under the leadership of St. Bernard of Clairvaux (1090-1153), with over 500 houses in Europe by the 13th century, but declined thereafter. The Cistercian's emphasis on manual labor, particularly farm labor, meant that the order played an important role in the economic progress of the 12th century and in the development of farming and marketing techniques. Reform movements occurred during the 16th and 17th centuries and the order ultimately divided into the Order of the Reformed Cistercians of the Strict Observance (often popularly called the Trappists) and the Cistercians of Common Observance. Today, there is a great amount of diversity among the monasteries of both orders and there has been a revival of literary work in both. Strict Observance is active in France, England and Poland while Common Observance is active in the United States and parts of Western Europe.