By the stipulation of Adam Lord Gifford, the lectures that for almost a hundred years have been offered by virtue of his bequest are to be aimed at an audience in which scholars active in the lecturer's field form at most a perceptible minority. Presenting a topic in the form of public lectures imposes certain limitations on handling one's material. One such limitation is the need to stress essentials and to paint the intellectual landscape in crisp and bold strokes. Since the topic discussed in these lectures spans much of cultural history, a selection of highlights was unavoidable.