worth, more than redeeming mankind and permitting it to enjoy a just will in accord with its intended nature. This interpretation is notable for permitting divine justice and mercy to be entirely compatible and has exercised immense influence over church doctrine, largely supplanting the earlier theory developed by Origen and Gregory of Nyssa that had focused primarily on Satan's power over fallen man. is often accounted Anselm's greatest work, but the legalist and amoral nature of the argument, along with its neglect of the individuals actually being redeemed, has been criticized both by comparison with the treatment by Abelard and for its subsequent development in Protestant theology. Other works Anselm's ("On Faith in the Trinity and on the Incarnation of the Word Against the Blasphemies of Roscelin"), also known as ("Letters on the Incarnation of the Word"), was written in two drafts in 1092 and 1094. It defended Lanfranc and Anselm from association with the supposedly tritheist heresy espoused by Roscelin of Compiègne, as well as arguing in favour of Trinitarianism and universals. ("On the Virgin Conception and Original Sin") was written in 1099. He claimed to have written it out of a desire to expand on an aspect of Cur Deus Homo for his student and friend Boso and takes the form of Anselm's half of a conversation with him. Although Anselm denied belief in Mary's Immaculate Conception, his thinking laid two principles which formed the groundwork for that dogma's development. The first is that it was proper that Mary should be so pure that—apart from God—no purer being could be imagined. The second was his treatment of original sin. Earlier theologians had held that it was transmitted from generation to generation by the sinful nature of sex. As in his earlier works, Anselm instead held that Adam's sin was borne by his descendants through the change in human nature which occurred during the Fall. Parents were unable to establish a just nature in their children which they had never had themselves. This would subsequently be addressed in Mary's case by dogma surrounding the circumstances of her own birth. ("On the Procession of the Holy Spirit Against the Greeks"), written in 1102, is a recapitulation of Anselm's treatment of the subject at the Council of Bari. He discussed the Trinity first by stating that human beings could not know God from Himself but only from analogy. The analogy that