In times such as this, when a region was suffering from disorder due to local conflicts, the local clergy, such as abbots, heads of monasteries, and bishops, would hold a town council. Invitations would be issued to nearby nobles demanding that they attend. Assuming the nobles showed up, the clergy would bring all the saints' relics they had available. These relics could include bits of bone, vials of blood, clothing from saints - anything that had at one time come in to physical contact with a saint. These would often be heaped in a pile or displayed dramatically and the clergy would use these relics to induce fear of the saints, fear of spiritual retribution, to intimidate the nobility to persuade them to promise to obey the Peace and Truce of God. The belief in the power of saints' relics was very strong.
Often, however, nobles simply did not show up and would ignore the invitation. In addition, nobles would often not swear to obey, or if they did, they would later break their promise. If a promise was made, it had to be renewed and documents show a renewal decade after decade in certain regions. The movement was not very effective. "In trying to control warfare without the use of physical coercion it rapidly foundered on the rocks of a violent feudal reality." (Richard Landes). However it set a precedent that would be followed by other successful popular movements to control nobles violence such as medieval communes, and the Crusades.
In addition to the Peace and Truce of God movement other non-violent, although less direct, methods of controlling violence were used by the clergy. By adding the religious oaths of fealty to the feudal act of homage, and in organizing rights and duties within the system, churchmen did their utmost to Christianize feudal society in general and to set limits on feudal violence in particular. This can be seen as combining the spiritual (potestas) and secular authority (auctoritas) in a dual concerted action that had defined the idea of Christian government since the fifth century.
The two movements began at separate times and places, but by the eleventh century they became synonymous as the "Peace and Truce of God".
At the Benedictine abbey of Charroux in La Marche on the borders of the Aquitaine "a great crowd of many people (populus) gathered there from the Poitou, the Limousin, and neighboring regions. Many bodies of saints were also brought there" bringing miracles in their wake. Three canons promulgated at Charroux, under the leadership of Gombald, Archbishop of Bordeaux and Gascony, were signed by the bishops of Poitiers, Limoges, Périgueux, Saintes and Angoulême, all in the west of France, beyond the limited jurisdiction of Hugh Capet. Excommunication would be the punishment for attacking or robbing a church, for robbing peasants or the poor of farm animals—among which the ass is mentioned but not the horse which would have been beyond the reach of a peasant—and for robbing, striking or seizing a priest or any man of the clergy who is not bearing arms. Making compensation or reparations could circumvent the anathema of the Church.
Children and women (virgins and widows) were added to the early protections. The Pax Dei prohibited nobles from invading churches, beating the defenseless, burning houses, and so on. Merchants and their goods were added to the protected groups in a synod of 1033. Significantly, the Peace of God movement began in Aquitaine, Burgundy and Languedoc, areas where central authority had most completely fragmented.
The tenth-century foundation of the Abbey of Cluny aided the development of the Peace of God. Cluny was independent of any secular authority, subject to the Papacy alone, and while all church territory was inviolate, Cluny's territory extended far beyond its own boundaries. A piece of land 30 km in diameter was considered to be part of Cluny itself, and any smaller monastery that allied itself with Cluny was granted the same protection from violence. This grant was given at a Peace of God council in Anse in 994. The monastery was also immune from excommunications, interdicts, and anathemas, which would normally affect an entire region. The abbey of Fleury was granted similar protection. Not coincidentally, many of the Cluniac monks were members of the same knightly class whose violence they were trying to stop.
"Peace of God" can also be used as a general term that means "under the protection of the Church" and was used in multiple contexts in medieval society. For example, pilgrims who traveled on Crusade did so under the "peace of God" ie. under the protection of the Church. This general usage of the term is not always related to the Peace and Truce of God movement.
Romans in the pagan traditions commonly used a similar phrase "peace of the gods", meaning when the gods were at peace, when the gods were not causing trouble, such as earthquakes or war, otherwise known as Ira Deorum (The Wrath of the Gods). The object of Roman religion was to secure the cooperation, benevolence, and "peace" of the gods, hence Pax Deorum.
The eighteenth-century historian Edward Gibbon detected a parallel among the pagan German tribes who worshipped a goddess of the earth who resided at the island of Rügen, who annually travelled to visit the tribes. "During her progress the sound of war was hushed, quarrels were suspended, arms laid aside, and the restless Germans had an opportunity of tasting the blessings of peace and harmony. The truce of God, so often and so ineffectually proclaimed by the clergy of the eleventh century, was an obvious imitation of this ancient custom.