The evolving connotation of “Christianity”

“The standard medieval phrase for what Christians today would call ‘Christianity’ was fides Christiana (‘Christian faith’). The difference is subtle, but profound. As with the rest of mankind, so in Christendom an age of faith is not an age of reification.

“It is only well after the Reformation that the term ‘Christianity’ becomes current, and only during the Enlightenment that it becomes standard. Even so, all through the eighteenth century and even beyond it refers to an ideal, first transcendent, then intellectual. Only within the last century or so has the meaning of an historical phenomenon come into use.

“In the first printed book-title in which I have found the word ‘Christianity’, it means ‘Christendom’. In the mid-sixteenth century it begins to appear in a few of the catechisms, including some versions of Calvin’s, as equivalent to ‘Christian doctrine’, ‘teaching about Christ’. It is also found in the ill-fated work of Servetus, both book and author perishing, But throughout the sixteenth century it remains comparatively rare.

“In the seventeenth century the word comes to be used in two senses. The first is a pietistic one, more or less equivalent to ‘Christ-like-ness’ or ‘Christian living’, almost as in St. Ignatius. Thus Johann Arndt inspired the later Pietist movement in Germany with a book that protested against rigid formalism and doctrinalism in the Church, calling instead for an inner personalizing of Christ in one’s heart. To this latter he gave the name das wahre Christentum. What he had in mind by this novel phrase may perhaps be rendered ‘true Christianness’; or better, ‘on being truly Christian. The sense of ‘Christlikeness’ seems striking in an English work later in the century entitled The Reasons of the Christian Religion: The first part, of Godliness. . . . The second part, of Christianity, though actually here the transition to our second meaning has begun. In the eighteenth century the first meaning persists, designating a quality of Christian living, But it had become rather rare.

“The other meaning, which develops with the Enlightenment, is systematic (ideal), and increasingly intellectualist. More and more this word, which had had only a meager history, came now to be used as the name of a system of beliefs. ‘The truth’ (or, truths) ‘of Christianity’ became a stock phrase. Whether ‘Christianity’ is or is not true, is or is not reasonable, became at this period brisk questions. This is well shown in such influential works as John Locke’s The Reasonableness of Christianity, just before the eighteenth century. Our interest here is not so much in why he thought or how successfully he argued that it was reasonable, as in reflecting on what it was that he thought reasonable; and on what it was that Tindal, a generation later, believed to be ‘as old as the creation’.

“Again it is possible to observe how those who disagreed, at any rate on the intellectual plane, acceded to the terms of the argument as postulated. Thus a 1691 title proclaims ‘Christianity a Doctrine of the Cross’, where the first three words are unwittingly as important as the last three. They are certainly as revealing, and a good deal more novel. And the first of the spate of pamphlets and books ensuing on Tindal’s highly provocative affirmation accepted his phraseology, and to some extent perhaps even the form if not the content of his conceptualizations. This was true also of many of the succeeding writers.”

— from William Cantwell Smith, The Meaning and End of Religion (Fortress Press, 1963)