a movement led by the medieval church, and later by civil authorities, to protect ecclesiastical property and women, priests, pilgrims, merchants, and other noncombatants from violence from the 10th to the 12th century.

The Peace of God arose in southern France, in particular Aquitaine, in the late 10th century in response to the growing inability of the royal and regional secular authorities to maintain order. The movement was rooted in the royal peace of the Carolingian dynasty in the 9th century, during which the sacred power of the ruler protected the weak of society, and reached back to pre-Carolingian times, when church councils in Gaul levied sanctions against individuals who attacked church property. The Peace of God began at a church council at Le Puy (975) and was promoted at a number of subsequent councils, including important ones at Charroux (c. 989 and c. 1028), Narbonne (990), Limoges (994 and 1031), Poitiers (c. 1000), and Bourges (1038). At these councils, churchmen gathered with regional lay authorities and attempted to make manifest God's protective power.

Most accounts of the peace gatherings are very brief and, therefore, offer limited insight into the nature of the movement. The accounts of the peace councils of Limoges, especially that of 1031, however, are much more detailed. Found in the writings of the monk Adhémar of Chabannes (Adhémar De Chabannes) (c. 989–1034), these accounts offer many insights into the character and purpose of the Peace of God movement. Adhémar's many references in his writings to the Peace of God make him the principal source on this phenomenon.

As the writings of Adhémar and his contemporaries reveal, the cult of the saints was of central importance to the movement. Relics (relic) from the surrounding areas were brought to each of the peace meetings and were thought to play an active role in them. In these veritable relic jamborees, the churchmen aroused the enthusiasm of the masses in attendance and proclaimed the intervention of the saints and the heavenly order to try to diminish the violence against church lands and the defenseless. Moreover, those in attendance would take oaths on the relics to uphold the Peace of God and to support the effort to reduce the violence of the period, which was often perpetrated by the growing number of castellans—fortress holders who were able to exercise power at the expense of the regional authority. The aim of these gatherings was to bring down to earth, through the agency of the saints, the peace of the heavenly order—a peace so clearly articulated by the great theologian and Church Father St. Augustine (Augustine, Saint) of Hippo in book 19 of The City of God.

Another factor in these gatherings seems to have been a keen sense of the proximity of the heavenly order, an apocalyptic expectation which explains, in part, the appearance of this movement at the time of the millennium. The apocalyptic character of the movement is confirmed by the high percentage of peace meetings that occurred in the decade before 1000 and again just before the year 1033, which was thought to be the 1,000th anniversary of the death, Resurrection, and Ascension of Christ. The council of Bourges bears witness that the hope of direct heavenly intervention was giving way to earthly arms bearing after the passing of the apocalyptic years. The warriors in attendance pledged to make war on the violators of the Peace of God. When their efforts resulted in a severe defeat at the hands of those who broke the peace, the movement suffered a serious setback, and by the middle of the 11th century the sanctified peace of southern France, which had been so dependent on the power of the saints as enforcers, was over.

The institutional peace, the attempt to achieve the ends of the Peace of God through legal actions based on both secular and canon law, continued to develop after the collapse of the sanctified peace movement. In northern France the dukes of Normandy and the counts of Flanders in the late 11th and the 12th century sought to enforce peace measures. The Normans in the same period also sought to establish the Peace in southern Italy and Sicily. In the German empire Henry IV was its champion in the late 11th century. The papacy, from the time of Pope Urban II (1088–99), lent its institutional weight to efforts to establish the Peace. In this manner the work of the early supporters of the Peace of God became a part of the institutional structure of the medieval society.

The Peace of God was important in a number of ways. In the early 11th century the Truce of God (God, Truce of), which sought to limit the number of days for warfare, evolved from it. The Peace of God also contributed to sacred militancy, which prepared the way for the Crusades. Although not itself a major success, the Peace of God contributed to the reestablishment of order in society in the 11th century, helped to spread recognition of the need to aid the poor and defenseless, and set the foundations for modern European peace movements.