Anyone, whether historian or theologian, who writes on John Calvin is likely to venture judgments concerning his place in Christian theology. Over the years the judgments have varied widely. Calvin's admirer Benjamin B. Warfield, for example, argued that the man the Roman Catholic Church judged a heretic actually marked a fresh epoch in the history of the catholic dogma of the Trinity. A less generous opinion, made from another ecclesiastical corner, is that Calvin was at best a mere epigone of Martin Luther, at worst a debaser of pure Reformation doctrine. At the end of the nineteenth century, it was said that Calvin represented a certain “atrophy” or “degeneration” of the idea of Protestantism (Ferdinand Kattenbusch), and in the mid-twentieth century one of the most widely used textbooks of church history in Germany could still present Calvin's theology in the form of six “deviations” from the theology of Luther (Kurt Dietrich Schmidt). Yet another well-known estimate from the last century judged Calvinism a more creative intellectual force in the modern world than Lutheranism but placed Calvin himself, with Luther, on the side of the “old Protestantism,” which only tried to give a new answer to an old medieval question, “What must I do to be saved?” (Ernst Troeltsch).