For Christianity, the 12th century represents a century of both internal and external changes. As the Crusades sought to impose a "universalized Christian faith" on those outside the religion, the internal mechanisms of the Church began to promote reforms that encouraged a unification of "doctrine, liturgy, piety and politics within Western Christianity. During this century, Christians began to live as a united and sacred community. Anselm of Canterbury and Peter Abelard made theological advances that brought about the unification of the Church and a radical change in Jewish-Christian relations. Their theories of the atonement began to shape the way Christians approached the Jews in matters of God. While Anselm's satisfaction theory of the atonement began to promote an appeal to reason among Christians toward Jews, Abelard's theory of moral influence of the atonement had the potential to encourage religious tolerance. Due to the political climate of that time, Anselm's theory took hold and became the leading theological argument against the Jews. To understand the importance that the evolution of atonement theory has had on Christian-Jewish 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 answer to the problem of evil. It states that the unification of the world with God's plan for it will result in the eventual victory of suffering and evil, if not in this world, then in the world to come. » The fall of humanity with Adam and Eve caused an imbalance. in the relationships between God and humanity. To achieve salvation, this iniquity had...... middle of paper...... 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. True Grace Ministries.Web. December 11, 2011. .Plantinga, Richard J., Thomas R. Thompson, and Matthew D. Lundberg. “The Reconciling Work of Jesus Christ.” An introduction to Christian theology. Cambridge, UK: CambridgeUP, 2010. 257-83. Print.Urban, Linwood. “Atonement.” A Brief History of Christian Thought. New York: OxfordUP, 1986. 101-24. Print.