The purpose of this doctoral dissertation is to contribute to the investigation of the regional organization of the system of settlements in the regions of the ‘Eastern Ro-man Empire’ (ERE) during the Early Byzantine period (EBP). By ‘EBP’ we mean the historical period comprising from the 4th to the end of the 6th century AD. By ‘regional organization’ we mean the administrative system of rule of the ERE with its five hierarchical levels of organization: a) the Empire; b) its division into admin-istrative regions (dioceses); c) the division of these into smaller regional unities (provinces); d) cities (polis), and e) market towns – villages (komes – choria) within each province. This system includes 3,048 units of analysis, settlements belonging to all hierarchical levels, and it yields their distinguishing features, through geographic - spatial and historical -cultural criteria. The dissertation’s object of study is the regional organization of settlements of the EBP, with emphasis on the 6th century. Its goal was the cartographic representation of the regions of the ERE and creation of maps that are defined by the data of politi-cal geography and described by the data of physical and cultural geography. Through the creation of historical sections in the 4th, 5th, and 6th centuries, diachronic regional transformations in the EBP were examined. A further goal was to create a database of cultural and geographic information concerning the entirety of settle-ments, in which are recorded the period of founding, the diachronic presence of each, with historical alterations of its name, including also its modern name and the state to which it belongs today. The dissertation conveys the totality of regional sites in the ERE, contributes to making the regional organization of settlements in the EBP better known, and enriches the diachronic study of both the settlements and culture of the Eastern Mediterranean. The dissertation is composed of three parts: Part I. Introduction; Part II: The regional structure of the Empire; Part III: Conclusions. Part I: Chapter 1 offers a scholarly overview and defines the goals, objects of study, and purpose (A.1), contents (A.2), primary sources (A.3) and methodology (Α.4), with a description of the techniques of cartography, map-making (atlas-making) and table-making. Part I also includes the historical framework of the EBP (Chapter 2), with its main socio-economic and political parameters. Chapter 3 concerns the geo-morphology and organization of the Empire (administrative boundaries, production activities and spatial administrative hierarchy, both political and ecclesiastical). Part II: Chapter 4 deals with the regional structure of the Empire and is allocated to a study of the organization of the 64 provinces in each of the six dioceses. The level of internal description of each diocese and province refers to variables that concern administrative division, geomorphology, and settlements (three levels: capitals, cit-ies, and market towns – villages). Two categories of variables were created: histori-cal-cultural data, and geographic-spatial data. The total of 3,048 settlements and the recording of variables along diachronic and synchronic axes, aided by the computer software SPSS (Statistical Package for the Social Sciences), allowed observations of a statistical nature as well as structural correlations between and among variables used for analysis. The data are complemented cartographically by 90 maps, done on the basis of the road network (3 variables: inter-regional, main, secondary) and their individual geomorphology. Part III: Chapter 5 describes the results of the analysis of the regional organization of the six dioceses, while Chapter 6 presents the results for the overall picture of the Empire (6.1), followed by the results for the articulation of the road network (6.2). These sub-sections are followed by the network of settlements (6.3), with conclud-ing observations of a statistical nature concerning the regional organization of set-tlements and the static/dynamic nature of the settlement system. The structure of the network of settlements is expressed through an attempt at modeling. In addition, basic statistical correlations and cross-tabulations concerning the hierarchy of set-tlements and their various parameters (period of founding, morphology of terrain, road network, transportation / communication features) are listed. The conclusions of this doctoral dissertation can be summarised as follows: During the Early Byzantine Period the Eastern Roman Empire, with its six large administra-tive dioceses and 64 provinces, occupied the regions around the Eastern Mediterra-nean, joining districts from three continents. The geomorphology and the landscapes of the region are varied and complex. Much of the land is mountainous though there are a few very important plains. There are eight types of vegetation varying from desert to beech forest. Olive cultivation accounted for an important percentage of the cultivatable land at that time.The primary sector was developed and there was self-sufficiency, which depended on cooperation between individual farmers as to what was grown. The secondary sector was also developed: there were government owned factories in many provin-cial capitals, as well as private artisan. There was also government owned mines and quarries for the excavation and the supply of raw materials.The network of settlements: their historical and cultural characteristics: 12,5% of the 3,048 settlements were founded in the Archaic period, 7.3% in the Classical, 17,8% in the Hellenistic, 42% in the Roman and 20,4% in the Early Byzantine pe-riod. Cross correlation between the number of settlements and their dates of founda-tion demonstrates that a much larger number of settlements arose after the Hellenis-tic period than were constructed before this period. It also shows that the Early Byz-antine provincial capitals were largely founded during the Hellenistic period. In ad-dition it shows that more than the 50% of the cities were founded in the Hellenistic and Roman period, while only about 12% were founded during the EBP. With re-gard to smaller settlements, we can observe that roughly 50% were founded in the Roman period, while only 25% were set up during the EBP. The fact that more than 80% of the total settlements in the Roman and EBP were minor settlements suggests a tendency towards agrarization of the society.The geographical - spatial characteristics and the morphology of the land: We ob-serve that 41% of the settlements were located between 0 – 300m, 12,5% were lo-cated between 300 – 600m and 43% were found higher in the mountains. From the cross-correlation of the timescale of the settlement with the geomorphology we see that 56% of the capitals and 50% of the cities are located in flat regions, while 47% of minor settlements are located in mountainous regions. 72% of settlements are close to water. 34% of the settlements are located on transregional road axes, 9% of these on main and the 14% on secondary roads, while 43% are not connected in this way. 14% of the settlements represent nodal points on the road system, 11% are ports, while nodes and ports constitute the 2%. The structure of the network of set-tlements ,using the capital city Constantinople as a point of reference, corresponds on the first level to a radial spatial model, the diffusion of which, extends as a spatial web into the three continents. On the second level there are individual linear spatial models that follow the seashores of the Mediterranean and the Euxeinos Pontos and follow passages to the hinterland, frequently through river valleys. The network of settlements and the road network are of course, closely linked.A substantial density of settlements, founded in the EBP, is found in Pontike Dioe-ceses, in the regions near Constantinople, as well as in the Anatolike Dioeceses, in the regions, that are related with the new religion, as the Palestine. There is a me-dium sized concentration of settlements in the Thrakike, Asiane and Aigyptiake Dioeceses, while there is a small concentration in the Dioeceses of Illyrikon. In gen-eral there is a large concentration of settlements in Greece; in the plateau of Asia Minor; in the southern parts of Syria and Palestine, (mainly in the coastal plateaus between Tyre and Gaza and following the banks of the Nile).In the Eastern Mediterranean the foundation of settlements began in the Archaic period and continued in the Classical period with the city – state as its main model. Slowly, during Hellenistic period minor size settlements began to dominate. In the Roman and Early Byzantine period, 80% of the new foundations were minor size settlements. Of the five historical periods, the foundation of settlements was at its most intense during the Roman period. The EBP continued this trend, though the development of new settlements was only half that which had been carried out under the Roman rule. The amount of flat land was very limited, yet the spread of settle-ments in flat and mountainous lands was almost the same. In the Roman and EBP, the higher percentage of settlements was founded in mountainous regions and these settlements were, in the beginning, small.The administrative structure had a pyramid-like form with the emperor at the top and a tree-like structure down the whole length of the hierarchy. The administrative power predominated over the military and there was a strengthened bureaucracy and a state centralism. The network was able to function because it was supported by two connected infrastructures: The first was concerned with the organized use of human resources: the bureaucracy: the administrators of the regional political power, whose main job was the collection of taxes and resources, and the control and the management of the means of production. The second was the physical infrastructure which enabled the trade, manufacture and transport generated by the administrators to be carried out, as well as facilitating the exchange of ideas, to and from the capital city. The network of roads ensured good communications and thus enabled this effi-cient system of central control to be implemented throughout the empire. The hier-archical structure at all organizational levels constitutes one from the distinctive features of the early Byzantine mode of production. This structure runs through the spatial dimension of the regional organization, that was cartographically surveyed on three levels: 1. On the land-planning level, which deals with the whole Eastern Roman Empire. 2. On the regional level, which was concerned with the Dioeceses. 3. On the provincial level, which deals with the Prov-inces. 3,048 settlements were recorded, located, categorized and organised in a data-base, a number that represents the total number of settlements known from archaeo-logical studies to have been active during the period being studied.From the above statements it can be seen that in the Early Byzantine period the Eastern Roman Empire was wealthy in the sense that it was productive, that there was a growing network of roads and dense pattern of settlements. The fact that many small settlements were founded at this time shows that not only was there a trend towards agrarization, but also suggests that the role of the cities was changing in those places where the number of small settlements increased within the same re-gion. The investigation of the regional organisation in the EBP shows that both the settle-ments at all levels, and the infrastructures of the Eastern Roman Empire were in good shape. It presents a picture of an empire, where the number the of rural and urban settlements is increasing while being organized in a hierarchical structure throughout the region. The thesis has made an effort to create a holistic picture of the geographical and administrative form of the Eastern Roman Empire, which can easily be analyzed in smaller spatial parts and recomposed in bigger, showing on each level the cultural characteristics of the settlements network, through the loca-tion, mapping and categorisation of the network. The present research was designed to contribute to the overall study of the regional landscapes of the Eastern Roman Empire and it contributes by analyzing regional organization of settlements in the Early Byzantine period. In this way it enriches the diachronic study of settlements of the Eastern Mediterranean and her culture with quantitative and qualitative elements.