This study into the person and the politics of the East Roman Emperor Leo attempts to reconstruct the events of the years AD 457-460 as exactly as possible. It revolves around the Council of Chalcedon and the religious and political conflict caused by the assassination of the Patriarch of Alexandria. The book also examines the tense relationship with the Western Empire, the Goths, and the mighty General Aspar, as well as the laws passed by the Emperor. An extensive excursus underpins and expands the chronological narrative in more detail.