Shortly after his conversion in 1929, C. S. Lewis wrote to a friend, When all is said (and truly said) about the divisions of Christendom, there remains, by Gods mercy, an enormous common ground. From that time on, Lewis thought that the best service he could do for his unbelieving neighbors was to explain and defend the belief that has been common to nearly all Christians at all times — that enormous common ground which he usually referred to as mere Christianity.
