Saint Demetrius was revered in the middle ages throughout Byzantium and in other countries in the Middle East and Eastern Europe. The Saint George of the Byzantine Empire, he was an important orthodox military saint said to have lived and been martyred in Thessaloniki in the early fourth century. By the tenth century, the cult of Saint Demetrius had grown exponentially and was an integral feature of life during the late Byzantine period, and particularly so in Thessaloniki. The martyred saint was the subject of miracle stories, panegyric speeches, biographies, prayer, hymns and encomia - a genre of literature originating from Classical Greece and particularly popular in the late Byzantine period. Here, Eugenia Russell explores the cult of Saint Demetrius and sheds light upon a turbulent period in which Byzantium faced political disunity and increasing external threat from the Ottoman Turks.