Thessaly, birthplace and cradle of Greek civilization, extended during the Early Christian, Byzantine and Post-Byzantine period over quite a remarkable area. Its boundaries were to the east the line starting from the mouth of Peneios River and reaching Thermopyles. To the south, Locrida, Phocida, Dorida and Aetolia. To the west, Athamania, Acarnania and Amphilochia, and to the north, the Macedonian districts of Elimea and Pieria. Already by the first century AD, inhabitants of Thessaly had become Christians, while until the fourth century AD only a few urban centres had developed, such as Larissa, Hypati, Demetrias and Phiotides Thebes. The latter, from the years of Constantine the Great on, grew and became an important Christian centre. This shows in the significant archaeological finds and by research and study of the bishops’ lists (Notita Dignitatum) . The large geographic expanse along with the fertility of the land of Thessaly attracted the “interest” – realized in invasions-of a great number of barbaric races and tribes (Visigoths, Huns, Slavs, Bulgarians, Serbs) and nonbarbaric ones (Franks, Catalans). Turkish hordes liberated Thessaly from the Serbs only to rule over it for almost five centuries (early fifteenth -late nineteenth century).