For Christianity, the 12th century represented a century of both internal and external changes. As the Crusades sought to impose a “universalized Christian faith” on those outside the religion, the inner workings of the Church began to promote reforms that encouraged a unification of “doctrine, liturgy, piety, and politics within Christendom Western". During this century, Christians began to experience a cohesive and sacred community. Anselm of Canterbury and Peter Abelard made theological advances that allowed for the unification of the Church and a drastic change in Jewish-Christian relations. Their theories of the atonement began to shape how Christians approached the Jews in matters relating to God. While Anselm's satisfaction theory of the atonement began to promote an appeal to reason among Christians regarding the Jews, Abelard's atonement theory of moral influence had the potential to encourage religious toleration. Due to the political climate of this time, Anselm's theory gained traction and became the leading theological argument against the Jews. To understand the significance that the evolution of atonement theory has had on Jewish-Christian relations, one must first understand what atonement theory implies in Christian practice. As Linwood Urban explains, the doctrine of atonement or restitution is: “…God's primary response to the problem of evil. It states that the unification of the world with God's plan for it will lead to the final victory of suffering and evil, if not in this world, then at least in the one to come." The fall of humanity with Adam and Eve caused an imbalance in the relationship between God and man. To gain salvation, this iniquity had... half the card... Alister, McGrath. Christian Theology: An Introduction, 2nd ed. (Blackwell, 1997): 407-408. Print. Carroll, James. "Anselm: why God became man." The Sword of Constantine: the Church and the Jews, a history. Boston, MA: Houghton Mifflin, 2002. 278-89. Print.Kessler, Edward. "Medieval Relations". An introduction to Jewish-Christian relations. Cambridge: Cambridge Univ., 2010. 102-23. Print.Mattison, Mark M. “The Meaning of the Atonement.” Auburn University. Ministers of True Grace.Web. December 11, 2011. Plantinga, Richard J., Thomas R. Thompson, and Matthew D. Lundberg. "The Reconciliatory Work of Jesus Christ." An introduction to Christian theology. Cambridge, UK: CambridgeUP, 2010. 257-83. Print.Urban, Linwood. "The Atonement." A brief history of Christian thought. New York: OxfordUP, 1986. 101-24. Press.