1098 · Schiavi di Abruzzo, Italy (written in exile)
Anselm of Canterbury Writes Cur Deus Homo
In 1098, Anselm, the Archbishop of Canterbury, completed Cur Deus Homo ('Why God Became Man'), a groundbreaking work of theology that offered the first systematic explanation of why God had to become human and die to save humanity.
Anselm was already famous for his earlier work, the Proslogion, which contained the ontological argument for God's existence. But Cur Deus Homo tackled a different and more practically urgent question: why did salvation require the Incarnation and the Cross? Why couldn't God simply forgive humanity's sin by decree? Anselm wrote the book while in exile from England, having clashed with King William II over the independence of the Church. Working in southern Italy, he structured the text as a dialogue between himself and a monk named Boso, who asks the hard questions that skeptics and honest believers both raise. Anselm's answer was what later theologians called the 'satisfaction theory' of atonement. Human sin, he argued, is an offense against the infinite honor of God. No finite being can repay an infinite debt. Only God can offer adequate satisfaction, but only a human being owes the debt. Therefore, only a God-man — someone who is fully divine and fully human — can bridge the gap. Christ's death was not a ransom paid to the devil, as some earlier theologians had suggested, but a free offering that restored the broken relationship between God and humanity. This argument changed Western theology permanently. Thomas Aquinas built on it. The Council of Trent assumed it. Even theologians who disagree with Anselm's framework still have to respond to it. The book remains one of the most important works of Catholic theology ever written.
Why it matters
Provided the first systematic theological explanation of the Incarnation and Atonement, establishing the satisfaction theory that shaped Catholic and Western Christian understanding of salvation for centuries.
What Happened
In 1098, while exiled from England due to conflicts with King William II, Archbishop Anselm of Canterbury completed Cur Deus Homo. Written as a dialogue, the work systematically explained why salvation required God to become human. Anselm argued that human sin created an infinite debt that only a God-man could repay, offering the 'satisfaction theory' of atonement that replaced earlier ransom theories and reshaped Western theology.
Why It Still Matters
Anselm's framework for understanding why Christ died remains the most influential explanation in Catholic theology. Thomas Aquinas refined it. The Council of Trent drew on it. When Catholics today speak of Christ's sacrifice 'satisfying' for sin, they are using language Anselm gave the Church. Even modern theologians who propose alternative models must engage with Cur Deus Homo as their starting point.