In the Rome of Constantine whether one worshipped the old gods or the new God was literally a question of life and death. In this book, the latest in the Terry Lecture series, the whole question of tolerance is reviewed and analyzed by the author from the focal point of the Roman ruler who first dared to decree that man could worship whom he pleased. The expectation of Constantine that some day all men would arrive by free consent at a unified faith has proved illusory, but the ground for tolerance which Constantine established is still valid today. What did the great Edict of Milan actually promise and what were the results? How did it come about? What was the climate of sensibility regarding tolerance in general and religious tolerance in particular? These are some of the questions the author seeks to answer. Professor Hermann Doerries, of the University of Goettingen, is the well-known biographer of Constantine. Translated by Roland Bainton.