This book retraces the life and work of Julius Pflug (1499-1564). Its interest is twofold: first, it allows us to survey the progress of the Lutheran Reformation, which Catholic apologists such as Pflug, Gropper, Witzel were unable to stop; secondly, as Pflug became entangled in all the political and religious events of his time, this biography reveals a wide range of personalities in Saxony and Germany and in imperial circles. On the other hand, if Pflug's work belongs to a period of transition, it retains through its irenic character an interest of topicality, while opinion is more sensitive to conciliation than to opposition of confessional differences.