Wilken traces the idea of religious freedom rather than the practice of toleration. His purpose is not to exonerate Christianity from its repressive past but to correct a common misunderstanding of the origins of the concept of liberty of conscience. This ideal emerged from faith rather than from indifference, skepticism, or hostility to religion. Wilken demonstrates this fact economically. Rather than making an exhaustive survey of the history of toleration, he offers a close reading of texts that reveal key lines of development in the Western concept of religious freedom: the conception of religious belief as an inviolable inner conviction that resists compulsion; the belief that this conviction—identified as conscience—is not passive, but compels action; and the distinction made between Caesar and God, that is, between earthly governments and spiritual authorities.
Ecclesiastical intolerance wonderfully demonstrates Lord Acton's thesis: "Power tends to corrupt and absolute power corrupts absolutely."