The dual focus of this class pertains to: a) make the students familiar with the study of Byzantine seals and b) provide them with elementary knowledge of the social, political and ecclesiastical institutions of the Byzantine Empire through the study of a specialized field. The seals, gold or silver, and especially the most numerous lead ones, were used by the emperor to the last literate citizen of the Byzantine empire, to seal and secure their correspondence; they are valuable historical evidence for: the study of the portraiture and genealogy, the administrative structure, the society, the administrative evolution of senior state officials and dignitaries, the history of the themata and other smaller administrative regions, the ecclesiastical history of a town or a wider geographical region. The core of the iconographic themes of the Byzantine seals includes saints and archangels, Jesus Christ, especially the Virgin Mary, rare scenes of the New Testament, and simple or metrical invocations of help and protection. All these religious representations, alongside with the accompanying inscriptions, which usually record the name, the administrative positions and the honorary titles of the owner, constitute a kind of identity, an additional element for the positive identification of a correspondence sender.