Paper for the conference “Olkas. From Aegean to the Black Sea. Medieval Ports in the Maritime Routes of the East”, Thessalonike, December 2013 (cf. http://www.olkas.net/com/9_Conference) . Published in: Medieval Ports in North Aegean and the Black Sea. Links to the Maritime Routes of the East. International Symposium Thessalonike, 4-6 December 2013. PROCEEDINGS. Edited by Flora Karagianni. Thessalonike 2013. In 2012, the Deutsche Forschungsgemeinschaft granted funding to the major collaborative research focus “Harbours from the Roman Period to the Middle Ages” (SPP-1630) with the aim of interdisciplinary research on the phenomenon of the “harbour”. One of these projects, “Ports and landing places at the Balkan coasts of the Byzantine Empire (4th-12th century). Monuments and technology, economy and communication”, focuses on the coastline from Dalmatia via the Aegean Sea to the western Black Sea and the Danube delta. Based on an analysis of all available sources and archaeological evidence, the aim is a complete survey of the coastal towns, bays and estuaries documented in these regions for the period 300-1204 AD; this should make possible differentiations with regard to the respective local significance of harbours for regional communication as well as for long-distance trade. The project will use the well-established methodological toolkit of the Tabula Imperii Byzantini for the survey of the historical and monumental evidence in order to augment the data basis of the already existing volumes of the TIB. At the same time, we intend to combine this information with digital geo-data both from published material (in print and online) as well as from own exploring voyages in the region; on this basis, modern tools of Geographical Information Systems (GIS) can be used for the analysis of maritime sites and transport systems. The aim of the present paper is a demonstration of the explanatory value of instruments of GIS as well as of network analysis on various levels for research on maritime sites, regions and networks with three short case studies in order to illustrate the potential of our approach within Byzantine maritime studies. These three case studies have been selected from regions within the modern borders of Greece (respectively beyond for the last one), which is the area of responsibility of the author of this paper in the above mentioned project.

Pre-Print, to be published in: Judith Pfeiffer (ed.), Proceedings of the International workshop “Maragha and Its Scholars. The Intellectual Culture of Medieval Maragha, ca. 1250-1550,” Istanbul, December 2013 [in preparation] The aim of this paper is a presentation of some aspects of the “infrastructure” for the significance of Maragha as centre of learning and intellectual exchange during the Mongol Period in Iran. It focuses on the embedding of the city in its hinterland with regard to landscape and environment as well as on its position within regional and over-regional route systems. Finally, one narrative of long-distance mobility across Mongol Eurasia is analysed with the help of network analysis in order to highlight the more far-reaching entanglements of Maragha. In general, some glimpses on the complex web of filaments, which linked the city to its near and wider environs, are provided.

Talk at the CML and Where East Meets West Seminar, University of South Denmark (Odense), August 19th 2015, see: http://www.sdu.dk/en/Om_SDU/Institutter_centre/C_cml/Calendar/WEMW

Draft for: “Complexity: a new framework to interpret ancient economic proxy data”. Book project and conference: Sagalassos, Sept. 11th-12th 2015 (cf. http://www.rsrc.ugent.be/sdep/complexity) Abstract: Based on the assumption that economic complexity is characterised by the interactions of “economic agents (who) constantly change their actions and strategies in response to the outcome they mutually create”, this paper presents how network models can be used a “proxies” for the mapping, quantification and comparison of pre-modern economic complexity. Network analysis provides tools to visualise and analyse the “inherent” complexity of various types of data and their combination (archaeological, geographical, textual) or even of a single piece of evidence. Equally, the relational approach invites to a structural and quantitative comparison between periods, regions and the economic systems of polities and empires. An increasing number of proxies of this kind allow us to capture the trajectories of economic complexity from antiquity into the middle ages beyond metaphors.

Ancient and medieval harbours connected via navigable and terrestrial routes could be interpreted as elements of complex traffic networks. Based on evidence from three projects in Priority Programme 1630 (Fossa Carolina, Inland harbours in Central Europe and Byzantine harbours on the Balkan coasts) we present a pioneer study to apply concepts and tools of network theory on archaeological and on written evidence as well as to integrate this data into different network models. Our diachronic approach allows for an analysis of the temporal and spatial dynamics of webs of connectivity with a focus on the 1st millennium AD. The combination of case studies on various spatial scales as well as from regions of inland and maritime navigation (Central Europe respectively the Seas around the Balkans) allows for the identification of structural similarities respectively difference between pre-modern traffic systems across Europe. The contribution is a first step towards further adaptions of tools of network analysis as an instrument for the connection and comparison of data across the projects of Priority Programme 1630.

This paper proposes to proceed from a rather metaphorical application of network terminology on polities and imperial formations of the past to an actual use of tools and concepts of network science. For this purpose, a well-established network model of the route system in the Roman Empire (ORBIS) and a newly created network model of the infrastructural web of Imperial China are visualised and analysed with regard to their structural properties. Findings indicate that these systems could be understood as large-scale complex networks with pronounced differences in centrality and connectivity among places and a hierarchical sequence of clusters across spatial scales from the over-regional to the local level. Such properties in turn would influence the cohesion and robustness of imperial networks, as is demonstrated with two tests on the model´s vulnerability to node failure and to the collapse of long-distance connectivity. Tentatively, results can be connected with actual historical dynamics and thus hint at underlying network mechanisms of large-scale integration and disintegration of political formations.

published in: Harbours and Maritime Networks as Complex Adaptive Systems, ed. by Johannes Preiser-Kapeller​ and Falko Daim. Verlag des Römisch-Germanisches Zentralmuseum​ 2015, 152 p. http://www.schnell-und-steiner.de/artikel_8560.ahtml?NKLN=12_RSA This paper provides an introduction into the concepts of complexity theory and of network analysis and their usage for the analysis of phenomena of maritime history. After an outline of characteristics of complex systems, the interplay between social and environmental factors for the selection, development, maintenance or abandonment of harbour sites is discussed. For this purpose, a simple mathematical port-harbour feedback model is developed. The second part focuses on the possibilities and problems to model and visualise networks of ports and routes on the basis of historical and archaeological data. Both complex systems and network models are introduced as potentially powerful heuristic tools for reflection on the entanglements between societies and environment as context for the emergence of harbours.

The centuries after the fall of Constantinople to the Crusaders in 1204 were characterized by the political fragmentation of the former imperial sphere of the Byzantine Empire; especially in the period between 1250 and 1453, attempts to establish hegemony by one of the local powers (Byzantium, Bulgaria, Serbia) were followed by phases of disintegration of these polities until the Ottoman State restored “imperial unity” in the region. While political border zones frequently changed, religious denominations (the orthodox Patriarchate of Constantinople, the autocephalous orthodox Churches of Bulgaria and Serbia, the Catholic Church, Islam) tried to preserve or expand their spheres of influence within the entire Balkans; furthermore, local and regional trading networks criss-crossed the region and integrated it in the late medieval “Worldsystem”, which was dominated in the Mediterranean by the cities of Venice and Genoa, which also possessed colonies in the Aegean. The concepts of network analysis allow us to understand these relations between different communities and authorities in a novel way; Michael Szell, Renaud Lambiotte and Stefan Thurner from the Vienna Complex Systems Research Group argued in a recent paper: “Human societies can be regarded as large numbers of locally interacting agents, connected by a broad range of social and economic relationships. (…) Each type of relation spans a social network of its own. A systemic understanding of a whole society can only be achieved by understanding these individual networks and how they influence and co-construct each other (…) A society is therefore characterized by the superposition of its constitutive socio-economic networks, all defined on the same set of nodes. This superposition is usually called multiplex, multi-relational or multivariate network.” (2) We will demonstrate the application of this “multiplexity”-approach for the analysis of various political, religious and mercantile networks which connected individuals and communities from the local and regional level to the level of the competing political, religious and economical centres in the late medieval Balkans within an across border zones. (3) We will present how we obtain relational data from our sources, such as the Register of the Patriarchate of Constantinople, which contains more than 700 documents for the years 1315 to 1402, and the integration of these data into networks of various scales; we will demonstrate how smaller networks can be connected to larger ones and how this influences the characteristics and topologies of networks. Finally, we will illustrate the applicability of this network analytical “toolkit” for other historical disciplines. Our paper is strongly connected to the study of Mihailo St. Popović, who will present historical-geographical aspects of these phenomena for one specific region. (

Selected bibliography on historical and archaeological network analysis, compiled for introductory workshops and course; besides historical and archaeological studies using concepts and tools of network theory, the focus is on introductory works and important methodological studies.

As network theory has become a focus of increasing attention in archaeological research, it has been demonstrated in recent years that questions regarding communication and organisation in past societies can be fruitfully discussed as network problems. While computer-based network modelling has proven an effective way of refining such problems, attempts to address these by applying methods of network analysis to archaeological data have faced complications, and sometimes led to confusing results. Archaeological datasets of a sufficient size to justify the application of statistical methods are usually structured by a multiplicity of parameters, which makes it unlikely that a two-dimensional mapping as nodes and edges may capture and represent patterns of culturally significant relationship in a coherent way. This paper argues that network analysis in archaeology should not be regarded primarily as a means of mapping out data pertaining to past relations and interactions, but as a method of framing, assessing, and criticizing such data.