As the first half of a two-year series, these lectures concern the Christian cultural history of Europe with a level of detail which the lectures on 'Religion and Culture' (1947) could not accommodate. They focus on the Roman adoption of Christianity and the influence of these developments on northern European culture during the early medieval period. As the second half of a two-year lecture series, these lectures focus on the middle and late medieval periods. Contrary to their common handle, the 'dark ages' of European history constitute a verdant period of religious culture. They focus on the institutions of European society for which Christianity is largely responsible, including civic organization, universities, and professional guilds.