An additional part of this reformation of Christian life was to somehow end, or deter, the incessant warfare that plagued the European community. The incessant Christian slaughter of Christians had led to the "truce of God" movement in the 11th Century as part of the general attempt at creating this new Christendom. Warfare was banned on the Sabbath. Under the influence of the great abbey of Cluny, a driving force in the reformation of the church, the truce was extended to holy days. In various territories it expanded to Advent, Lent, Easter and Pentecost. By the middle of the 11th Century it was closely knit to the Peace of God movement, which protected Church property and the poor from war. Violation of the Peace or the Truce was considered grounds for excommunication. While it seems contradictory to encourage a Crusade in the interest of peace, there was certainly the papal hope that by turning the incessant warring fervor outward in the purpose of defending Christendom there was greater purpose than the continuing scandal of Christians slaughtering Christians.