The West
In Western Europe the great Cistercian monastic reform movement of the Benedictine Order (now known as the Trappists) arose. This movement’s greatest representative, Bernard of Clairvaux (1090–1153), was an ascetical, mystical theologian and church activist of aristocratic background. He promoted the Second Crusade (of 1147), and theologically he fought against Peter Abelard (1079–1142), another important early Scholastic theologian and author of the famous Sic et Non. The Carthusian movement of intensely contemplative, semi-eremetic monasticism, founded in 1084 by Bruno, expanded rapidly in this era.
Together with the centralizing of Papal power and the victory of the Papacy over the secular rulers in the controversy over lay investiture, the 12th century also saw the rise of the Victorine school of Augustinian theology, led by Hugo (d. 1141) and Richard of Saint Victor (d. 1173). Another major Scholastic theologian, Peter Lombard (c. 1100–1160), wrote his very influential Sentences in the 1150s.
On the more popular level, the Waldensian movement arose in the 1170s, led by a merchant of Lyons named Valdes. This very energetic layman emphasized itinerant, Scripture-based lay preaching, voluntary poverty, and works of charity. The various Waldensian groups suffered various forms of persecution at the hands of the Roman Catholic Church during the succeeding centuries. Finally in the 16th century, most of them merged with various Protestant groups.
Also, the dualist heretical movement known as the Cathari arose in Germany around 1140, under the influence of Bogomilism from Eastern Europe. By around 1200 the Cathari had grown and spread to such an extent that they were the principal target of the Inquisition that was instituted in the early 13th century. In southern France these heretics were known as Albigensians.
In 1147, the Second Crusade was launched with the goal of winning back the Crusader Kingdom of Edessa which had fallen to the Muslims. Preached by Bernard of Clairvaux, this crusade was led by King Louis VII of France and Holy Roman Emperor Conrad III. These Crusaders further alienated the Byzantines by their uncouth behavior. At the same time, the Westerners had learned to hate the Greeks, considering them to be deceitful, and their Church heretical. The chronicler Odo of Deuil listed the various practices and beliefs of the Greek Christians now scorned by the Westerners, and he recorded their willingness to kill the Greeks as heretics. More and more, the Latins dreamed of seizing Constantinople for themselves, and they were urged to do so by some of their own clergy.
Meanwhile, the Greek Church’s consternation at the extension of Papal claims was eloquently expressed in a letter by Archbishop Nicetas of Nicomedia written to Bishop Anselm of Havelberg, in Germany.
Archbishop Nicetas of Nicomedia
writing to Bishop Anselm of Havelberg
My dearest brother, we do not deny to the Roman Church the primacy among the five sister Patriarchates, and we recognize her right to the most honorable seat at an Ecumenical Council. But she separated herself from us by her own deeds, when she assumed a monarchy which does not belong to her office. . . . How shall we accept decrees from her that have been issued without consulting us, and even without our knowledge?
If the Roman pontiff, seated on the lofty throne of his glory, wishes to thunder at us from on high, and if he wishes to judge us and even to rule us and our churches, not by taking counsel with us but at his own arbitrary pleasure, what kind of brotherhood or even what kind of parenthood can this be? We would be the slaves of such a church, and the Roman see would not be the pious mother of sons but a hard and imperious mistress of slaves. . . . In such a case what could have been the use of the Scriptures? The writings and the teachings of the Fathers would be useless. The authority of the Roman pontiff would nullify the value of all because he would be the only bishop, the sole teacher and master.