This is the third volume of the first part of a comprehensive catalogue of middle Byzantine authors and their texts, written between AD 641 and 867. A brief biographical description of each author is followed by a bibliography with details of sources and references to manuscripts. This volume begins with Leon (catalogue number 4271) and ends with Placentius (number 6265).This is the third volume of the first part of a comprehensive catalogue of middle Byzantine authors and their texts, written between AD 641 and 867. A brief biographical description of each author is followed by a bibliography with details of sources and references to manuscripts.