With this edition of two distinct studies, we believe that we connect scientifically research issues that have a common denominator. This is the fact that their background is based on the universal perspective. Thus, in the first study, the successful universal actions of Justinian are proven in a practical way in his effort for doctrinal agreement with Rome. In the second study, besides proving the paternity of a neglected kontakion from a doctrinal point of view, we want to highlight his movement around the goal of his writing, which was his relationship with the convening of synods and his doctrinal problematic. [...]

(from the book's preface)