We refer to the Middle Ages as ages of faith; a time in which men believed a heavenly Jerusalem above the sky much as they believed an earthly Sion beyond the sea; when the whole of their thought was of a piece with their theology...those were days when a thoughtful soul here or there could realize some unity of mental vision. The fact should be admitted, however we regard it - whether as the stultifying tyranny of dogma or as an enviable single-mindedness; an ideal too easily realized, no doubt, in a plentiful dearth of empirical knowledge, and yet establishing a standard after which perplexed modernity may strive.